tag:theconversation.com,2011:/us/topics/crime-scene-investigation-31081/articlesCrime Scene Investigation – The Conversation2023-05-18T02:02:23Ztag:theconversation.com,2011:article/2049212023-05-18T02:02:23Z2023-05-18T02:02:23ZForensics are different when someone dies in a body of water. First, you need to locate them<figure><img src="https://images.theconversation.com/files/526663/original/file-20230517-17-ox0x4u.jpg?ixlib=rb-1.1.0&rect=98%2C44%2C5784%2C3943&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Roxane 134</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/police-diver-wet-suit-employed-emergency-1578479857">Shutterstock</a></span></figcaption></figure><p>While the iconic “crime scene – do not cross” tape may be a familiar sight on land, it’s a different story when it comes to water.</p>
<p>With no way to tape off an entire lake or a slice of the vast expanse of the ocean, investigations in, under or beside the water present a unique challenge. This work is not just due to suspicious criminal activity, but also search and recovery operations or accidents. </p>
<p>With the human body not equipped to survive in water, many fatalities are recorded every year as a consequence of <a href="https://www.theguardian.com/australia-news/2022/dec/28/10-australians-dead-in-water-accidents-as-lifesavers-urge-caution-in-heightened-danger-of-holidays">natural death</a> or <a href="https://7news.com.au/news/western-australia-police/womans-body-found-floating-in-fremantle-fishing-harbour-sparking-mystery-death-probe-c-9060847">suspected murder</a>. Bodies can be found not only in the ocean, but also <a href="https://www.thesun.co.uk/tvandshowbiz/12115770/naya-rivera-cause-of-death/">lakes</a>, <a href="https://www.9news.com.au/national/western-australia-news-body-of-man-discovered/8b7769c5-48c2-48a0-a8a1-4e17a3dae3de">rivers</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/23568015/">wells</a>, <a href="https://www.cbsnews.com/news/murky-water-hid-dead-body-in-pool-for-2-days/">swimming pools</a> and <a href="https://www.theguardian.com/world/2013/feb/21/body-found-hotel-cistern-water">cisterns</a>.</p>
<p>Sometimes the scenario is more complex, such as a 2021 case when a body was discovered <a href="https://www.9news.com.au/national/wa-murder-human-remains-found-in-wheelie-bin-floating-in-perth-dam/413c4059-491b-4d05-8e9f-33e1e9a0568a">concealed in a wheeled bin at the bottom of a dam</a>, or when the severed foot of fraudster Melissa Caddick was <a href="https://www.theguardian.com/australia-news/2022/sep/29/melissa-caddicks-severed-foot-likely-floated-to-beach-after-93-days-underwater-expert-says">found in a shoe washed up on a beach</a>.</p>
<p>Investigators called to such scenes must rely on specialised techniques and technology to gather evidence and piece together what happened. Sometimes they are supported by experts in the niche and multidisciplinary field of “aquatic forensics”, such as <a href="https://www.abc.net.au/news/2022-02-15/shipwreck-animal-bones-forensic-science-murdoch-university/100829198">our research team</a>.</p>
<p>The sheer size of a body of water can make it difficult to know where to start, but there are always four main questions to drive the investigators’ work. Who are the victims? How did they die? When did the death occur? And where did it happen?</p>
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Read more:
<a href="https://theconversation.com/how-do-police-forensic-scientists-investigate-a-case-a-clandestine-gravesite-recovery-expert-explains-171959">How do police forensic scientists investigate a case? A clandestine gravesite recovery expert explains</a>
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<h2>Finding the body</h2>
<p>Sometimes the first issue is finding the deceased person. Depending on the body of water and the circumstances surrounding the case, teams of divers can be dispatched to conduct a search. </p>
<p>Since investigators and pathologists usually do not experience the actual scene and <a href="https://myjms.mohe.gov.my/index.php/JCHS/article/view/13166">will see the victim only when retrieved</a>, underwater images and memories provided by divers become essential.</p>
<p>However, the safety of the divers always comes first. Divers can operate only for a certain period in an underwater scenario. This is determined by factors such as depth, water temperature, currents and waves that affect the divers’ breathing rate and air consumption from the tank.</p>
<p>Narrowing the search area is a pivotal fist step. <a href="https://phys.org/news/2015-09-cadaver-dogs-underwater-corpses.html">Specially trained dogs</a> can detect the scent of submerged human remains from the surface, if it’s not too deep. Technology can help, too – satellites and <a href="https://www.imarest.org/themarineprofessional/on-the-radar/5693-forensic-oceanography-challenges-in-police-search-operation">oceanographic data</a> can help locate floating objects, and <a href="https://link.springer.com/chapter/10.1007/978-3-642-04253-9_182">sonar</a> can scan the water to detect any objects at the bottom, including a body.</p>
<p>Divers can then take what’s known as a <a href="https://www.sciencedirect.com/science/article/pii/S2589871X23000165">visual record of the scene</a> directly, or they can use remotely operated vehicles equipped with cameras. It is also important to use a reference photo scale – in the water objects appear up to 25% closer and 33% larger than their real size.</p>
<p>Despite the best efforts, depth, distance from the target and clarity of the water can affect the quality of the images. Some underwater areas have zero visibility, making the investigation more <a href="https://pubmed.ncbi.nlm.nih.gov/28480488/">challenging and potentially unsafe</a>.</p>
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<a href="https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sign on the side of a footpath that says police diving is underway and people should stop their boats before proceeding" src="https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526664/original/file-20230517-27-62vdej.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">For searches conducted underwater, such as in this Manchester city canal in 2019, police can employ specially trained divers.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/manchester-united-kingdom-12th-nov-2019-1558006295">Shutterstock</a></span>
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<h2>Identifying and retrieving the body</h2>
<p>Sometimes, identifying the victim is straightforward, for example in cases with <a href="https://7news.com.au/news/nsw/details-emerge-as-witness-describe-efforts-to-save-sydney-dad-of-two-who-drowned-retrieving-sons-ball-from-lake--c-5188684">witnesses present</a>. However, bodies can be unrecognisable after a time spent underwater. Being submerged causes <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474513/">several changes</a> due to temperature, currents, and <a href="https://pubmed.ncbi.nlm.nih.gov/29445874/">interactions with animals</a> and obstacles.</p>
<p>For example, cold and wet environments like the ocean cause fat tissue to turn into a waxy substance (<a href="https://pubmed.ncbi.nlm.nih.gov/33596512/">adipocere</a>) in less than <a href="https://pubmed.ncbi.nlm.nih.gov/17316224/">40 days</a>. Limb loss is also common – investigators might have to identify a body based only on <a href="https://pubmed.ncbi.nlm.nih.gov/10882826/">some parts</a>. If a body loses a foot, it may be found floating thanks to the <a href="https://pubmed.ncbi.nlm.nih.gov/30453176/">buoyancy offered by shoes</a>.</p>
<p>As with cases on dry ground, clothing and personal items such as wallets and <a href="https://www.research.ed.ac.uk/en/publications/forensic-jewellery-a-design-led-approach-to-exploring-jewellery-i">jewellery</a> can assist the identification process. To avoid losing personal items during recovery, <a href="http://www.disastermedtech.com/amphibious-body-bag.html">amphibious body bags</a> have been developed. They allow body collection directly from the water, retaining associated objects but allowing the water to drain away.</p>
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<h2>Drowned or already dead?</h2>
<p>One of the main questions is if the death happened in the water or elsewhere, with the body dumped afterwards. There are an estimated 236,000 annual <a href="https://www.who.int/news-room/fact-sheets/detail/drowning">drowning deaths worldwide</a>.</p>
<p>Investigators can also be called upon a body found at sea after <a href="https://www.theguardian.com/world/2015/nov/07/fisherman-lost-at-sea-436-days-book-extract">months gone missing</a>, or <a href="https://www.perthnow.com.au/news/nsw/caucasian-mans-head-washes-up-in-a-bag-on-rottnest-island-beach-ng-ee7ec09b774ea580384c70c8068cba1b">remains washed up on a beach</a>. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/16378701/">Drowning is one of the most difficult diagnoses</a> in forensic pathology. <a href="https://pubmed.ncbi.nlm.nih.gov/35725698/">It is based</a> on a few scattered findings, such as frothy fluid in the airways, lung damage, and fluid in the upper gastrointestinal tract.</p>
<p>Another tool is the <a href="https://pubmed.ncbi.nlm.nih.gov/26256845/">diatom test</a> – it compares microscopic algae found in the tissues of the body with the one present in the water where the body was recovered. For highly decomposed bodies, new <a href="https://pubmed.ncbi.nlm.nih.gov/33147546/">molecular</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/35725699/">artificial intelligence</a> and “<a href="https://pubmed.ncbi.nlm.nih.gov/31282630/">virtopsy</a>” (virtual autopsy) technologies are fast developing.</p>
<p>Sometimes drowning is the mechanism of death, but there may have been other underlying causes – such as a cramp, a heart attack, drugs or an accident of some sort. It takes careful interpretation to discern these.</p>
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<img alt="A diver in a wetsuit on the sea floor manipulating instruments" src="https://images.theconversation.com/files/526750/original/file-20230517-23-6ertl7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/526750/original/file-20230517-23-6ertl7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526750/original/file-20230517-23-6ertl7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526750/original/file-20230517-23-6ertl7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526750/original/file-20230517-23-6ertl7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526750/original/file-20230517-23-6ertl7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526750/original/file-20230517-23-6ertl7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Rossella Paba conducting an underwater archaeology survey.</span>
<span class="attribution"><span class="source">Rossella Paba, Author provided</span></span>
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<h2>Old tools and new technologies are helping</h2>
<p><a href="https://isprs-archives.copernicus.org/articles/XL-5-W5/7/2015/">Photogrammetric surveys</a> developed to map submerged archaeological sites, and underwater drones equipped with multiple sensors, special lights and acoustic imaging technologies to locate submerged targets, can help to create a 3D image of the underwater area. This helps to distinguish large items, such as shipwrecks and vehicles, bodies or <a href="https://link.springer.com/article/10.1007/s00414-017-1546-1">bones</a>, and pieces of <a href="https://pubmed.ncbi.nlm.nih.gov/33218795/">clothing</a>.</p>
<p>After retrieval, macro and microorganisms can provide information on the <a href="https://pubmed.ncbi.nlm.nih.gov/25538026/">provenance</a>, the <a href="https://www.frontiersin.org/articles/10.3389/fvets.2019.00404/full">causes of death</a> and the <a href="https://theconversation.com/how-centuries-old-bones-from-australias-historic-shipwrecks-can-help-us-solve-crimes-174963">submersion time</a>.</p>
<p>Unlike the standardised methods on dry land, procedures in underwater criminal scenarios are still being developed. Forensic scientists are also borrowing the knowledge, techniques and tools from other fields, such as underwater archaeology and marine biology – but without the crime scene tape.</p><img src="https://counter.theconversation.com/content/204921/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>You can’t tape off an entire ocean. But ‘aquatic forensics’ is an emerging field, with techniques borrowed from archaeology, marine biology and more.Paola A. Magni, Adjunct Research fellow, The University of Western Australia; Research Fellow, Harry Butler Institute, Senior Lecturer in Forensic Science, Murdoch UniversityEdda Guareschi, Adjunct Lecturer in Forensic Sciences, Murdoch UniversityRossella Paba, PhD candidate, University of Cagliari, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1748702022-01-13T19:10:39Z2022-01-13T19:10:39ZCrime won’t stop because of COVID. So how should we protect crime scene investigators?<p>COVID may have curtailed travel, hospitality, education and entertainment, but crime scene investigation never stops.</p>
<p>As a forensic scientist, researcher and lecturer, I know first-hand the risks and challenges crime scene investigation (CSI) teams have faced over the past two years as we’ve grappled with the realities of operating amid the threat of COVID.</p>
<p>CSI units present a unique challenge, as investigators often work at close quarters for prolonged periods. Yet surprisingly, until now, there has been very little adjustment to existing crime scene procedures.</p>
<p>When COVID first appeared, guidelines were quickly <a href="https://pubmed.ncbi.nlm.nih.gov/32705079/">introduced</a> in a <a href="https://www.cdc.gov/coronavirus/2019-ncov/community/guidance-law-enforcement.html">range of countries</a> for forensic autopsies of COVID-positive cases and the handling of infected biological samples, but not for CSI protocols more generally.</p>
<h2>How should CSI teams be protected?</h2>
<p>One possibility is CSI teams could adopt the <a href="https://www.researchgate.net/publication/350823604_Crime_scene_investigation_in_a_CBRN_context%20https://www.amazon.com.au/Hot-Zone-Forensics-Biological-Radiological/dp/0398074658">existing protective measures</a> used for chemical, biological, radiological or nuclear incidents. </p>
<p>Those measures were largely developed in the wake of the 9/11 terror attacks, and in response to broader concerns about terrorism that began to emerge in the 1990s.</p>
<p>But these safety precautions are burdensome, time-consuming and expensive, particularly for local and regional law enforcement agencies, and are not necessarily useful when dealing with a virus.</p>
<p>Officers dealing with identifying a potential toxic warfare agent, for example, would need much more bulky equipment than the standard PPE used to prevent COVID infections.</p>
<p>And let’s not forget the role of our law enforcement agencies also includes many other tasks, such as crime prevention and public order, not just identifying, securing and providing evidence in a criminal court. In an ideal world, each police department would have its own specialist forensic agents. But the reality, especially in small cities and remote areas, is that officers are trained for every task, including collecting forensic evidence.</p>
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<img alt="Officer in anti-terrorism protective suit" src="https://images.theconversation.com/files/440602/original/file-20220113-21-11w1o0u.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440602/original/file-20220113-21-11w1o0u.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440602/original/file-20220113-21-11w1o0u.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440602/original/file-20220113-21-11w1o0u.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440602/original/file-20220113-21-11w1o0u.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440602/original/file-20220113-21-11w1o0u.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440602/original/file-20220113-21-11w1o0u.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Equipment designed to protect officers from terrorism-related hazards are often too impractical to use on a daily basis.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Visit_Image_Page_170921-A-MC386-0001.jpg">Katelyn Strange/US Army/Wikimedia Commons</a></span>
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<p>All over the world during the 2020 lockdowns, minor offences such as burglaries and car thefts <a href="https://theconversation.com/some-crimes-have-seen-drastic-decreases-during-coronavirus-but-not-homicides-in-the-us-142718">declined</a>. But there was no drop in serious crimes, such as homicide and domestic violence. </p>
<p>In fact, COVID has arguably created new types of incidents to investigate, such as <a href="https://7news.com.au/lifestyle/health-wellbeing/man-found-dead-in-queensland-hotel-quarantine-c-4088960">suspicious deaths in hotel quarantine</a>.</p>
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Read more:
<a href="https://theconversation.com/some-crimes-have-seen-drastic-decreases-during-coronavirus-but-not-homicides-in-the-us-142718">Some crimes have seen drastic decreases during coronavirus — but not homicides in the US</a>
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<p>COVID looks set to be with us for some time yet. So what is the best way to protect our CSI teams in an affordable and practical way?</p>
<h2>COVID-safe crime scenes</h2>
<p>One place to look for ideas is Italy, which has so far <a href="https://www.statista.com/statistics/1104964/coronavirus-deaths-since-february-italy/">recorded</a> 5.6 million COVID cases and almost 140,000 deaths. </p>
<p>Together with Enrico Di Luise of the Italian Military Police Laboratory of Forensic Biology in Messina, I have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8375245/">published</a> a world-first set of recommendations to make forensic operations possible across the different phases of crime scene management, from evidence collection in the field to analysis in the lab.</p>
<p>Briefly, our recommendations include:</p>
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<li><p><strong>CSI call policy</strong>. To ensure maximum preparedness, operations call centre staff should be trained to ask for information about the health conditions of the victim(s) and other people involved in the case, including their travel history and contact history.</p></li>
<li><p><strong>Equipment preparation and sanitation</strong>. Any object, if contaminated at the scene of a crime, can potentially spread infection to the rest of the CSI team. To guard against this, team members should each be given their own individual set of equipment, such as briefcases, evidence boxes, chemical reagent sets, and ultraviolet flashlights. Disposable materials or tools should be treated as medical waste and placed in a designated area of the crime scene. Reusable items should be disinfected at the crime scene with sanitiser or bleach, and back at headquarters should be sanitised a second time by mechanical or chemical disinfection, or thermal sterilisation in an oven called an autoclave. This should be done in a dedicated room by staff wearing appropriate PPE.</p></li>
<li><p><strong>Working groups</strong>. CSI team should be able to maintain independent forensic capacity, including experts in at least the areas of forensic biology, fingerprint analysis and photography, plus the ability for one team member to also take on the task of team leader. This is the only feasible way to maintain teams with full operational ability. Officers should be organised into small, non-interchangeable teams, so if one or more members of a particular team falls ill, another team can step in without risk of exposure.</p></li>
<li><p><strong>Procedure at the scene</strong>. Regardless of the scenario, CSI operators must consider every crime scene as a “hot zone”. Limiting the number of operators present in a room or small space at any given time is crucial. We have proposed a new general layout by which crime scenes can be divided into different areas, including one-way paths in and out, and a dedicated “clean area”.</p></li>
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<a href="https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Crime scene layout diagram" src="https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=439&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=439&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=439&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=552&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=552&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440598/original/file-20220113-35588-1kqnjt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=552&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Suggested generic layout for a crime scene, to minimise chances of cross-infection with COVID.</span>
<span class="attribution"><span class="source">Di Luise & Magni/Science & Justice</span></span>
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<ul>
<li><strong>Chain of custody</strong>. A correct chain of custody for evidence is crucial to any forensic case. But different types of evidence have different infection potential, and often have to be treated in different labs, by different staff or on different time frames. Until now, details such as time and exact location have rarely been included in routine traceability recordings, but should now be included. These details could be vital in tracing the movement of potentially contaminated items.</li>
</ul>
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Read more:
<a href="https://theconversation.com/covid-has-changed-policing-but-now-policing-needs-to-change-to-respond-better-to-covid-164959">COVID has changed policing — but now policing needs to change to respond better to COVID</a>
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<img src="https://counter.theconversation.com/content/174870/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paola A. Magni does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There are no COVID-specific protocols for forensic officers collecting evidence from crime scenes. New recommendations suggest how teams and their equipment can be reorganised to minimise the risk.Paola A. Magni, Senior Lecturer in Forensic Science, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1719592021-11-18T02:19:57Z2021-11-18T02:19:57ZHow do police forensic scientists investigate a case? A clandestine gravesite recovery expert explains<figure><img src="https://images.theconversation.com/files/432536/original/file-20211117-17-12mhnhc.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5729%2C3739&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Brendan Chapman</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Recent high-profile missing persons cases, including that of William Tyrrell – who went missing in Kendall, New South Wales, at the age of three in 2014 – have focused public attention on the forensic practices involved in crime scene investigations. </p>
<p>As a forensic scientist who has worked at thousands of homicide, sexual assault and serious crime scenes, I can tell you this process is not as straightforward as depicted on popular true crime shows.</p>
<p>I <a href="https://scholar.google.com.au/citations?user=RxkDXXAAAAAJ&hl=en">research</a> and teach <a href="https://www.murdoch.edu.au/thisisfreethinking/home">forensic science at Murdoch University</a> and specialise in <a href="https://www.murdoch.edu.au/news/articles/cold-case-review-at-murdoch">cold-case</a> techniques and clandestine gravesite recovery. Here’s what typically happens behind the lines of police tape when forensic teams are at work.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/this-is-going-to-affect-how-we-determine-time-since-death-how-studying-body-donors-in-the-bush-is-changing-forensic-science-117662">'This is going to affect how we determine time since death': how studying body donors in the bush is changing forensic science</a>
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</p>
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<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432534/original/file-20211117-17-a8pr7v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The author teaches students clandestine grave site evidence collection techniques to Murdoch University students.</span>
<span class="attribution"><span class="source">Brendan Chapman</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>The crucial first moments</h2>
<p>In the first moments after a major crime, what has happened is often a mystery. </p>
<p>Like a scene from a painting, it’s as if time stood still; many regular household items sit as they did before the violent event took place. Investigators take great care not to disturb the initial scene, lest valuable evidence be lost.</p>
<p>The first task is to record everything as it appears in incredible detail – by video, photo and in written notes. Even items that may first appear innocuous can later take on new significance.</p>
<p>This stage is vital; years later, this may be the only way cold-case teams can virtually revisit the scene to identify new clues. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432531/original/file-20211117-28-9dneev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The first task, before anything in the scene is disturbed, is to record everything as it appears.</span>
<span class="attribution"><span class="source">Brendan Chapman</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Evidence testing and collection</h2>
<p>As the forensic investigation unfolds, information and evidence are gathered and given to investigators at the crime scene. This helps provide context to guide the search for evidence.</p>
<p>The crime scene team works meticulously to identify and “field-test” items (meaning tests are done in situ) before securing them in bags. </p>
<p>In some cases, that’s by using chemicals and testing kits to identify body fluids or other traces associated with the crime. </p>
<p>We also use some very high-tech torches that can emit a specific type to light to help us see otherwise invisible clues. This works a bit like the lighting in nightclubs that might expose lint on your black outfit.</p>
<p>At this stage, the best crime scene examiners invoke the scientific method, proposing <a href="https://wires.onlinelibrary.wiley.com/doi/10.1002/widm.1354">hypotheses</a> as to what has happened, and then searching for evidence that may refute their suggestion. </p>
<p>Theories are presented and then ruled out in place of new theories as new evidence emerges. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432295/original/file-20211116-27-102xibz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The crime scene team works meticulously to identify and field test items of evidence before securing them in bags.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Testing for traces of blood, semen and other body fluids</h2>
<p>On the scene, forensic investigators have a suite of tools to help identify body fluids such as semen and blood.</p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2523691/?page=1">Kastle–Meyer test</a>, deployed to test for the possible presence of blood, has been used since the early 20th century.</p>
<p>A chemical called phenolophthalin is dropped onto the suspected sample, followed quickly by a drop of hydrogen peroxide. These chemicals can detect the blood ingredient haemoglobin. If it rapidly turns pink, there’s a good chance there’s blood in the sample.</p>
<p>A different method called the acid phosphatase test, which can detect an enzyme secreted from the prostate gland, is used to identify the presence of semen. A prepared chemical is dropped onto a sample of the suspected stain; a colour change from clear to dark purple suggests the likely presence of semen.</p>
<p>You may also have heard of investigators using <a href="https://www.abc.net.au/news/2021-11-17/william-tyrrell-investigation-technology-explained/100626684">luminol</a>, which can detect old blood stains or traces a person has tried to scrub away. The investigator sprays luminol and other chemicals on a darkened area; a blue glow suggests traces of blood may be present.</p>
<p>For all these tests, and everything we do as forensic investigators, meticulous records are kept about both observations and ideas. These notes will eventually become part of the huge case file that goes to court. </p>
<h2>Different types of forensic experts work together</h2>
<p>There are many different types of specialist crime scene investigators, such as:</p>
<ul>
<li><p><strong>fingerprint specialists</strong>, who use chemicals and powders to visualise fingerprints invisible to the naked eye and determine if they’re good enough to compare with prints on a database</p></li>
<li><p><strong>bloodstain pattern analysis experts</strong> who, like Dexter from the eponymous crime show, observe the shape of blood droplets or marks in an effort to reconstruct a bloodshed scenario</p></li>
<li><p><strong>physical evidence comparison experts</strong>, who record evidence such as shoe impressions or tool marks to compare with objects at the scene (for example, was <em>this</em> screwdriver used to create <em>that</em> mark on a window frame?)</p></li>
<li><p><strong>ballistics and firearms experts</strong>, who identify and analyse evidence such as gunshot residues and fired bullets. They can also reconstruct shooting events to determine trajectories and distances</p></li>
<li><p><strong>clandestine grave recovery experts</strong> (like me!), whose knowledge of the natural processes after death can help <a href="https://link.springer.com/article/10.1007/s11896-021-09457-8?wt_mc=Internal.Event.1.SEM.ArticleAuthorOnlineFirst&utm_source=ArticleAuthorOnlineFirst&utm_medium=email&utm_content=AA_en_06082018&ArticleAuthorOnlineFirst_20210521">locate and exhume grave sites</a> using painstakingly careful archaeological approaches. </p></li>
</ul>
<p>Other specialised forensic practitioners include pathologists, <a href="https://theconversation.com/trust-me-im-an-expert-forensic-entomology-or-what-bugs-can-tell-police-about-when-someone-died-124416">insect experts</a>, anthropologists, biologists and chemists. </p>
<p>Forensic investigations are most successful with a <a href="https://www.emerald.com/insight/content/doi/10.1108/JCP-09-2019-0038/full/html">multidisciplinary</a> team, which allows for many different opinions and ideas. </p>
<p>Specialists must work together to ensure one person’s evidence-collection method doesn’t ruin another specialist’s chance to use their own techniques.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/trust-me-im-an-expert-forensic-entomology-or-what-bugs-can-tell-police-about-when-someone-died-124416">Trust Me, I'm An Expert: forensic entomology, or what bugs can tell police about when someone died</a>
</strong>
</em>
</p>
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<h2>Clandestine gravesites</h2>
<p>Outdoor scenes present extra challenges, as evidence can be damaged or destroyed by weather, wildlife and the landscape itself. Clandestine gravesites, however, can help preserve clues underground.</p>
<p>It’s not easy to find a hidden burial site; even a freshly dug gravesite, if done well, can be difficult to identify in an expansive bush scene. </p>
<p>Investigators will be looking for areas where the ground looks disturbed or spots where vegetation has grown unusually lushly (caused by the decomposition of a body underneath).</p>
<p>Investigators may also deploy cadaver dogs to search for human remains, or <a href="https://www.abc.net.au/news/2021-11-17/william-tyrrell-investigation-technology-explained/100626684">ground-penetrating radar</a>, which uses radio waves to identify changes in the soil underground.</p>
<p>Once a grave is identified, you can’t just roughly dig it up; the grave fill must be gradually removed using small brushes and shovels, like those used on archaeological dig sites.</p>
<p>All removed soil is sifted and searched for tiny pieces of evidence; even a tiny fibre or hair could connect the grave to a suspect. </p>
<p>Even the sidewalls of the grave can offer clues about the type or shape of the shovel used to dig it. </p>
<p>Layer by layer, we work down until we reveal the deceased person at the bottom of the grave. Utmost care is taken here, as repatriation of the remains to loved ones is a pivotal part of the process of gaining closure.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432533/original/file-20211117-23-qhvavi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">It’s not easy to find a hidden burial site; even a freshly dug gravesite, if done well, can be very difficult to identify in an expansive bush scene.</span>
<span class="attribution"><span class="source">Brendan Chapman</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Time is of the essence</h2>
<p>All evidence has a life span. The sooner forensic scientists can identify and analyse a piece of evidence, the better the chances are of it producing a result. </p>
<p>This can be one of the greatest challenges in a cold case, where a crime scene has been changed by the elements over many years.</p><img src="https://counter.theconversation.com/content/171959/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brendan Chapman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As a forensic scientist who has worked at thousands of homicide, sexual assault and serious crime scenes, I can tell you the process is not as straightforward as depicted on popular true crime shows.Brendan Chapman, Senior Lecturer in Forensic Science, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1441462020-08-14T12:20:37Z2020-08-14T12:20:37ZForensic breakthrough helps explain how innocent people’s clothing fibres could end up at crime scenes<figure><img src="https://images.theconversation.com/files/352562/original/file-20200812-16-1t6nl0c.jpg?ixlib=rb-1.1.0&rect=108%2C31%2C5067%2C3414&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/forensic-expert-collects-evidence-crime-scene-1157300962">Zoka74/Shutterstock</a></span></figcaption></figure><p>Every time you put on a coat, hug somebody or sit on a sofa you leave behind <a href="https://doi.org/10.1016/S0015-7368(75)70932-5">tiny little fibres</a> from <a href="https://doi.org/10.1016/j.forsciint.2017.07.035">your clothing</a>. You also pick up fibres left behind by other people. This movement of fibres is known as <a href="https://www.taylorfrancis.com/books/e/9781315156583">fibre transfer</a> and forensic scientists can use this to <a href="https://www.sciencedirect.com/science/article/abs/pii/S135503060471713X?via%3Dihub">solve crimes</a>. </p>
<p>Textile fibres are one of the most important types of evidence in forensic science. And have been pivotal in solving some of the UK’s most notorious crimes – such as the murders of <a href="https://www.theguardian.com/uk/2011/oct/28/joanna-yeates-case-vincent-tabak">Joanna Yeates</a>, the <a href="http://news.bbc.co.uk/1/hi/england/suffolk/7228106.stm">Ipswich serial killings</a>, the <a href="https://www.theguardian.com/uk/2003/nov/25/soham.ukcrime">Soham murders</a> and the <a href="https://www.theguardian.com/uk/2011/may/26/john-cooper-murders-finally-solved">Coastal Path murders</a>, to name a few. </p>
<p>But establishing textile fibre links is only half the battle for forensic scientists working on criminal cases. What is equally, if not more, important, is to work out how the fibres actually got there in the first place.</p>
<p>To date, it’s largely been assumed that fibre transfer only occurs when two surfaces touch. So, for example, when the front of your jumper touches the shirt of someone you hug, or when the back of your trousers touches the sofa you sit on. But we now know this is not necessarily the case.</p>
<h2>A new discovery</h2>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S0379073820302942">new research</a> has found a new way that fibres can be transferred: “contactless airborne transfer”. This is when fibres move from one garment to another without contact. So, for example, imagine there are two people in the same room, but they don’t touch each other. It’s possible that fibres from person A’s clothing could transfer through the air, to person B’s clothing (and vice versa).</p>
<p>From the perspective of an investigation, this means that, under certain conditions, fibres found on a person could have been passively transferred rather than through direct involvement in a crime. </p>
<figure class="align-center ">
<img alt="Forensic scientist in lab." src="https://images.theconversation.com/files/352563/original/file-20200812-22-jnbffh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352563/original/file-20200812-22-jnbffh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352563/original/file-20200812-22-jnbffh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352563/original/file-20200812-22-jnbffh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352563/original/file-20200812-22-jnbffh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352563/original/file-20200812-22-jnbffh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352563/original/file-20200812-22-jnbffh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Our findings will have a major implication for fibre evidence in criminal cases worldwide.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/forensic-science-lab-scientist-examining-textile-710798314">Microgen/Shutterstock</a></span>
</figcaption>
</figure>
<p>In our experiment we used everyday garments - jumpers, long sleeved tops and fleeces – that were fluorescently dyed. This allowed us to track the airborne transfer of their fibres between garments. </p>
<p>One participant wearing a fluorescent garment stood in one corner of an elevator and another wearing a non-fluorescent black top stood in the diagonally opposite corner. Both participants remained in the elevator (without touching each other) for 10 minutes. During this time the elevator operated as normal and non-participants of the study entered and exited as usual. </p>
<p>Following the experiment, the black top of the recipient was photographed using UV-imagery techniques to determine the number of fibres transferred. The results of the study proved that not only can textile fibres actually transfer between garments without physical contact, but they can do so in relatively high numbers. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/352732/original/file-20200813-24-1qdwkr9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/352732/original/file-20200813-24-1qdwkr9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=513&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352732/original/file-20200813-24-1qdwkr9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=513&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352732/original/file-20200813-24-1qdwkr9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=513&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352732/original/file-20200813-24-1qdwkr9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=645&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352732/original/file-20200813-24-1qdwkr9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=645&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352732/original/file-20200813-24-1qdwkr9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=645&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fibre transfer during the experiment.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Often in a criminal case the finding of just a few fibres can be considered significant. So the fact that up to 66 fibres were transferred in a single experiment, was considerably higher than anticipated. </p>
<p>That said, not all garments we tested transferred fibres to the same extent. We found the type of fibres the donor garment was constructed from and its ability to shed those fibres was key in contactless fibre transfer. The type of clothing worn by the recipient also impacted transfer, as did the movement of people and the opening or closing of the elevator doors. </p>
<h2>Fibre evidence</h2>
<p>When forensic evidence is presented in court, a forensic scientist is responsible for evaluating the significance of that evidence. And our new findings may be particularly relevant for those specific cases where a small number of fibres are found and the circumstances are right for contactless fibre transfer to take place. </p>
<p>For example, imagine two people were in an elevator and one alleges to have been assaulted by the other. If hundreds of the victim’s fibres are found on the suspects clothing, it’s highly unlikely that contactless transfer alone is the reason for the all the fibres. But if only a few fibres are found, contactless transfer is more viable.</p>
<p>And in this way, the results of our study can be used as a baseline in the evaluation of fibres found as part of a case – and will also help to increase the robustness and validity of forensic evidence being presented in court.</p><img src="https://counter.theconversation.com/content/144146/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research shows fibres can transfer between people without any contact.Kelly Sheridan, Senior Lecturer in Forensic Science, Northumbria University, NewcastleMatteo Gallidabino, Senior lecturer in Forensic Science, Northumbria University, NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1254672019-10-29T15:54:14Z2019-10-29T15:54:14ZCSI: current research into the impact of bias on crime scene forensics is limited – but psychologists can help<figure><img src="https://images.theconversation.com/files/299200/original/file-20191029-183128-8wd1f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/collection-fingerprints-different-types-isolated-on-1167082960">Shutterstock</a></span></figcaption></figure><p>When a jury decides the fate of a person, they do so based on the evidence presented to them in the courtroom. Evidence obtained from forensic analysis, such as DNA analysis, is often interpreted as <a href="https://journals.sagepub.com/doi/10.1375/acri.37.2.231">strong evidence by jurors</a>.</p>
<p>This perception of forensic evidence is enhanced by popular TV shows like <a href="https://www.theguardian.com/tv-and-radio/2010/feb/14/beginners-guide-to-csi">CSI: Crime Scene Investigation</a>, where physical evidence is used to solve murders in a “whodunit” showdown between deductive cops and crafty criminals covering their tracks. All it takes is the right evidence to piece the story together.</p>
<p>But recent <a href="https://www.sciencedirect.com/science/article/pii/S0379073805005876">research</a> suggests that the reality of forensic analysis is that it can be subjective and fallible. For instance, forensic evidence can sometimes be ambiguous because of factors such as the presence of DNA on samples that originates from more than one person. </p>
<p>When forensic evidence is ambiguous, contextual information (such as knowledge of a confession) may influence how forensic examiners evaluate the evidence. This distortion in their evaluation is called <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/acp.1130">contextual bias</a> and has been stated to be a <a href="https://www.jstor.org/stable/25475240?casa_token=3i09Qs0DnDwAAAAA:fjkDrxe1-WB753LCDBJn8pQsDWcsleIaXmTrwY5u8KrPtzC02P-QESgyJAT0xNYK1rqKmxoKUIfSh2Z6Uh-hRVmLnPIi01FcGy7BAIstre-xQC5gOZfw&seq=1#metadata_info_tab_content">reason</a> why miscarriages of justice occur. </p>
<p>Our <a href="http://oro.open.ac.uk/67262/">research</a> agrees with this recent research that contextual information may influence the decisions of forensic examiners. But this may not necessarily be a bad thing. We believe it is premature to remove context from forensic analysis. Contextual bias on the part of a forensic examiner does not necessarily mean that errors will be made.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tpPkmDeS3Dg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>It is difficult for psychologists in the UK to make recommendations about the effects of context on forensic examiners because the research to date has been fairly limited, particularly in the the way it has been conducted.</p>
<p>For example, some studies had a very <a href="https://www.sciencedirect.com/science/article/pii/S0160932703000681">small sample size</a>. Some <a href="https://www.sciencedirect.com/science/article/pii/S0379073805005876">lacked a control group</a>. In others, <a href="https://www.sciencedirect.com/science/article/pii/S0160932703000681">accuracy was not measured</a>. This means that the researchers could not know for certain if participants would have performed differently if no contextual information had been available to them. So it has been <a href="https://www.sciencedirect.com/science/article/pii/S0379073805005876">difficult to generalise</a> about the effects of contextual bias on forensic examiners’ decisions.</p>
<h2>Bias does not equal error</h2>
<p>But our study presents the idea that contextual information does not necessarily always lead to inaccurate decision making. </p>
<p>First, forensic evidence will be generated from both the crime scene and <a href="https://www.sciencedirect.com/science/article/pii/S2211368117302863">the suspect</a>, meaning that the fingerprints left at a crime scene are <a href="https://www.researchgate.net/publication/325768928_Are_forensic_scientists_experts">more likely than not</a> to match the fingerprints of the suspect. For this reason, contextual information (such as knowledge of a confession) that biases forensic examiners towards finding a match may lead to more accurate decisions being made. </p>
<p>Contextual information may also inform the examiner which tests to conduct. If the examiner knows which questions they must answer, then they may avoid worthless tests. But this also means they may overlook something. For example, one piece of <a href="http://www.forensicdna.com/assets/how-much-should-an-analyst-know_.pdf">research</a> cited a rape-homicide case. In this case, a forensic laboratory was told by detectives to only analyse the evidence for semen samples. This meant that the forensic examiners missed blood samples that turned out to be integral to the case. </p>
<p>Based on this example, researchers stated that contextual ignorance may have more of a <a href="http://www.forensicdna.com/assets/how-much-should-an-analyst-know_.pdf">negative effect on forensic decisions</a> than contextual bias. This view is supported by psychological <a href="https://www.taylorfrancis.com/books/e/9780429248306/chapters/10.1201/9781420047523-20">studies</a> which have shown that biased decision processes can lead to accurate decision outcomes. </p>
<h2>Impact on jury decisions</h2>
<p>Despite the potential positive effects, it may remain <a href="https://www.tandfonline.com/doi/full/10.1080/00450618.2010.541499">ethically and legally inappropriate</a> for forensic examiners to use contextual information. For instance, jurors may interpret the different types of evidence, such as a confession and forensic evidence, as being independent of one another. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/299213/original/file-20191029-183128-12ph6j8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">DNA analysis is often considered as ‘strong’ evidence by jurors.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/inside-crime-laboratory-testing-blood-stains-355757636">Shutterstock</a></span>
</figcaption>
</figure>
<p>But if contextual information such as a confession aids the interpretation of forensic evidence, jurors may incorrectly think that each piece of evidence independently supports the other when this is not actually the case. This means that jurors could be <a href="https://www.tandfonline.com/doi/full/10.1080/00450618.2010.541499">overestimating</a> the chances of a defendant being guilty.</p>
<p>Our review suggests that concerns relating to the study of contextual bias in forensic examiners – small sample size, no accuracy measure and failure to use a control group – makes it difficult for implications and recommendations to be drawn. </p>
<p>We suggest that future research employs the skills of both forensic examiners and cognitive psychologists. Then that both skill sets can be used to create realistic experiments. Examiners have the necessary knowledge of both lab environments and forensic evidence, but we believe that access to this knowledge will help psychologists design more rigorous experiments targeted towards the study of contextual bias in forensic examiners. Only then will we discover can proper conclusions be drawn about whether contextual bias is a help or a hindrance.</p><img src="https://counter.theconversation.com/content/125467/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Research into contextual bias needs to be more rigorous so recommendations can be made about its effect on forensic analysis.Lee John Curley, Lecturer in Psychology, The Open UniversityJames Munro, Psychology Researcher, Edinburgh Napier UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/908512018-02-18T19:15:55Z2018-02-18T19:15:55ZSeeing the unseeable: how viewing crime scene photos can be beneficial<figure><img src="https://images.theconversation.com/files/205221/original/file-20180207-28321-18ij3we.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A forensic photograph featured in the film Unnatural Deaths. </span> <span class="attribution"><span class="source">courtesy NSW Police</span></span></figcaption></figure><p>Forensic photographs are taken by specialists as part of police investigations. These crime-or-accident scene images are included in a brief of evidence, used to prove illegal acts, and to establish how and why a person died. Afterwards, once coronial and criminal processes have concluded, the forensic evidence, including the photos, returns to a notional police archive. </p>
<p>The subjects of police photographs range from the seemingly unremarkable – empty rooms, fences, staircases, windows, pathways, roads, kitchen tables, hallways, plates, cups – through to confronting pictures associated with cases of injury and death: the body at the scene, blood, disfiguring injuries, skin discolouration.</p>
<p>Bereaved families are discouraged by police and other personnel from viewing the images associated with the death of their loved one. Relatives applying for access to the material often find themselves making repeated requests but authorities will routinely refuse them on the grounds that the images will cause them distress. </p>
<p>While this gatekeeping is understandable, a number of social workers are advocating for families to be <a href="http://www.tandfonline.com/doi/abs/10.1080/02682621.2017.1305042">given a choice to access and view the archived material.</a> </p>
<p>Early research indicates that the experiences of bereaved people are complex and varied. For some victims’ parents, partners, sons, daughters, extended family, and friends, the fact of the death is enough. For others, though, there is a need to see the images in order to piece together the minutiae of the events: the scene; the way their loved one lay; what happened before, during and after; what their loved one did and saw. </p>
<p>More than that, the images can also address relatives’ deep need to mentally process the death. Sometimes families feel misplaced remorse. Despite playing no part in the events of the death of their loved one, they believe that perhaps they could have <a href="https://www.katerossmanith.com/small-wrongs/">somehow prevented the occurrence.</a> They imagine they could have intervened, that they could have done something. In such circumstances, the police photos can become profoundly meaningful. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/205007/original/file-20180206-14089-j2kdo0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Forensic photograph featured in Unnatural Deaths.</span>
<span class="attribution"><span class="source">courtesy NSW Police</span></span>
</figcaption>
</figure>
<p>As Kate Rossmanith’s documentary <a href="https://www.theguardian.com/australia-news/video/2018/feb/19/unnatural-deaths-the-emotional-power-of-forensic-photographs-video">Unnatural Deaths</a> illustrates, bereaved relatives can find unexpected solace in such images. For instance, Juliet Darling’s partner was <a href="https://www.allenandunwin.com/browse/books/general-books/biography-autobiography/A-Double-Spring-Juliet-Darling-9781743315057">attacked and killed in 2009.</a> Says Darling: </p>
<blockquote>
<p>You think about it so much, and your mind goes to the scene, and tries to re-live these experiences that aren’t even yours. My wild imaginings made it almost seem to me that I had actually been at the crime scene, when in fact I hadn’t been there.</p>
</blockquote>
<p>It was helpful, she says, to view the crime scene photos: “To see just the bare facts.”</p>
<h2>The coronial perspective</h2>
<p>Coroners considering a case will often look at the photographs of the crime or accident scene. The task of a coroner is to determine, if possible, whether a death has taken place (if there is no body, it may be far from certain); and if so, the identity of the person who has died (sometimes it is difficult to ascertain); as well as the date and place of death, and the physical cause and circumstances of it. </p>
<p>The answer is not always available from the medical history or records. It may not even be available from a physical examination of the body. In such cases, the circumstantial evidence becomes crucially important. When memories fade and arguments arise, crime scene images can settle many questions.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/205008/original/file-20180206-14089-1ro2ekh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/205008/original/file-20180206-14089-1ro2ekh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/205008/original/file-20180206-14089-1ro2ekh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/205008/original/file-20180206-14089-1ro2ekh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/205008/original/file-20180206-14089-1ro2ekh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/205008/original/file-20180206-14089-1ro2ekh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/205008/original/file-20180206-14089-1ro2ekh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Forensic photograph featured in Unnatural Deaths.</span>
<span class="attribution"><span class="source">courtesy NSW Police</span></span>
</figcaption>
</figure>
<p>Strangely, coroners often find the photographs much more viscerally affecting than viewing a body in the mortuary. This is because the mortuary is a sterile, technical environment – bright lights, steel tables, instruments, people in scrubs; it brings home to coroners, in a way that photographs cannot, that the essence of whatever animated this person before has left him or her.</p>
<p>Photographs, however, taken at the scene with a body <em>in situ</em>, convey sadness and the prematurity of a living person’s death. </p>
<h2>‘Afterlives’ of evidence</h2>
<p>There is a growing public interest in forensic photos. Since the early 1990s historical forensic photographs have come to be seen as <a href="https://sydneylivingmuseums.com.au/exhibitions/city-shadows">important material culture</a>. At the same time, digital capture and transmission technologies have accelerated the mass circulation of forensic images: in the name of “open justice”, and with the sanction of the courts, media agencies regularly publicise selected evidence during coronial and criminal proceedings, with the material readily shared online. </p>
<p>Yet discussion regarding how we approach such forensic material has significantly lagged behind these rapid developments in transmission capabilities. As legal scholar Katherine Biber has pointed out, we lack a forum to think about, what she terms, the “afterlives of evidence”. She calls for <a href="https://academic.oup.com/bjc/article-abstract/53/6/1033/417928">“a jurisprudence of sensitivity”</a> when it comes to courts’ decision-making regarding the release of evidence into the public sphere. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/205009/original/file-20180206-14078-1w42w4i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Forensic photograph featured in Unnatural Deaths.</span>
<span class="attribution"><span class="source">courtesy NSW Police</span></span>
</figcaption>
</figure>
<p>The issue not only involves <em>what</em> material is made available to us, but <a href="http://www.tandfonline.com/doi/abs/10.1080/13576275.2017.1291603?journalCode=cmrt20"><em>how</em> we look at it</a>, the <em>interlocution</em> that accompanies our looking, and the resulting questions we ask ourselves. In order to continue developing a nuanced approach to forensic images, it is critical to consider the sometimes surprising ways in which police photographs are meaningful to those people closest to them: police photographers, coroners, and, crucially, victims and their families. </p>
<p>Bereaved families strive to comprehend that there is nothing they could have done to prevent, or hold off, the death of their loved one. Viewing the crime-and-accident scene images can offer a path to healing. </p>
<p>We need to move away from approaching grief as a medical event subject to diagnosis, and instead turn our attention to the diverse needs of family members as they comprehend the realities of death, and the meanings of that death in their own lives. </p>
<p>For relatives, the forensic images may form an integral part of the narrative they will develop to make sense of their loved one’s death. We need to make sure families are able to access this material – but crucially, with skilled support, such as provided by social workers in some forensic and coronial offices – and to make the choice that is right for them about seeing it.</p>
<p>The photographs offer opportunities for restoration – not only for people directly affected by tragic events, but for the broader community too. In this way, the photos can be seen as important to larger human experiences of reconciliation that go well beyond official forensic and procedural processes. </p>
<p><em>Kate Rossmanith’s micro-documentary, <a href="https://www.theguardian.com/australia-news/video/2018/feb/19/unnatural-deaths-the-emotional-power-of-forensic-photographs-video">Unnatural Deaths, can be seen on The Guardian</a>. It explores the experiences of bereaved relatives as they view crime scene photos after the sudden death of a loved one.</em></p>
<p><em>The crime and accident scene photographs featured in Unnatural Deaths were supplied courtesy of New South Wales Police under the condition that the cases with which they are associated remain anonymous. The images depict a range of forensic investigations, including accidents, break-ins, thefts, as well as coronial cases.</em></p><img src="https://counter.theconversation.com/content/90851/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Bereaved families strive to comprehend that there is nothing they could have done to prevent the death of their loved one. Viewing the crime-and-accident scene images can offer a path to healing.Kate Rossmanith, Senior Lecturer in Cultural Studies, Macquarie UniversityHugh Dillon, Adjunct Professor of Law, UNSW SydneyJane Mowll, Lecturer in Social Work, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/855342017-10-23T19:07:51Z2017-10-23T19:07:51ZFingerprinting to solve crimes: not as robust as you think<figure><img src="https://images.theconversation.com/files/191295/original/file-20171022-13934-bnw0xm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's a margin of error in relying on fingerprinting to catch criminals. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/police-takes-fingerprints-criminal-law-concept-524699446?src=3-DyRQZYszIkTc0lL081Ww-1-58">from www.shutterstock.com </a></span></figcaption></figure><p>Police have used fingerprint evidence to catch and convict criminals for <a href="http://www.hup.harvard.edu/catalog.php?isbn=9780674010024">more than 100 years</a>. It’s a commonly used technique in Australia: more than <a href="http://www.police.vic.gov.au/content.asp?Document_ID=771">10,000 fingerprint matches</a> were made in Victoria alone last year.</p>
<p>But in a <a href="https://www.aaas.org/report/latent-fingerprint-examination">recent report</a>, the American Association for the Advancement of Science has questioned the scientific validity of fingerprint analysis.</p>
<p>The report is a reminder that although fingerprinting is an essential tool for investigating crime, <a href="http://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=7201&context=jclc">it’s not infallible</a>. We need to minimise the inappropriate application of the “science” of fingerprinting, and reduce repeats of <a href="http://digitalcommons.law.ggu.edu/ggulrev/vol37/iss1/4/">miscarriages of justice</a> linked to fingerprint analysis that have already occurred.</p>
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Read more:
<a href="https://theconversation.com/forensic-evidence-largely-not-supported-by-sound-science-now-what-67413">Forensic evidence largely not supported by sound science – now what?</a>
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<p>Most notoriously, <a href="https://oig.justice.gov/special/s0601/exec.pdf">Brandon Mayfield</a>, an American lawyer, was wrongly linked by four fingerprint experts to the 2004 Madrid train bombing. He was arrested and detained for two weeks, before investigators realised that an Algerian man, Ouhnane Daoud, was the real source of the print. </p>
<h2>How does fingerprint examination work?</h2>
<p>Everybody’s fingers, palms and soles have “friction ridges” on them. These ridges occur in patterns (such as <a href="https://forsci.wikispaces.com/Fingerprinting">arches and loops</a>) that contain specific features (for example, ridge endings and dots). </p>
<p>Fingerprint examiners <a href="https://www.crcpress.com/Fingerprints-and-Other-Ridge-Skin-Impressions-Second-Edition/Champod-Lennard-Margot-Stoilovic/p/book/9781498728935">use these patterns</a> and features to compare an unknown (or “latent”) print with a known print, to determine if they may have come from the same person.</p>
<p>In Australia, police use the <a href="https://www.acic.gov.au/our-services/biometric-matching/national-automated-fingerprint-identification-system">National Automated Fingerprint Identification System</a> – a database with more than <a href="https://www.australianpolice.com.au/dactyloscopy/automated-fingerprint-identification-system-afis/">2.6 million</a> sets of fingerprints - to narrow down the field of fingerprints to compare. But the final decision about whether there is a “match” is made by a person.</p>
<p>A 2010 report, published by the US National Institute of Justice, concluded that <a href="http://www.crime-scene-investigator.net/fingerprintsourcebkchp6.pdf">automated systems</a> were significantly less accurate than well-trained examiners at making comparisons between latent and known prints.</p>
<h2>Problems with the underlying science</h2>
<p>Until the mid-2000s, little scientific research had been done on most forensic disciplines, including fingerprinting. This lack of research became widely publicised in 2009, when the US National Research Council published a <a href="https://www.ncjrs.gov/pdffiles1/nij/grants/228091.pdf">landmark report</a> on the forensic sciences. </p>
<p>It found that the only forensic method that had been rigorously validated was nuclear DNA analysis. All other forensic sciences – including fingerprinting – lacked a proper scientific foundation. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-the-crime-scene-to-the-courtroom-the-journey-of-a-dna-sample-82250">From the crime scene to the courtroom: the journey of a DNA sample</a>
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<p>When examining this issue again in 2016, the President’s Council of Advisors on Science and Technology (<a href="https://obamawhitehouse.archives.gov/sites/default/files/microsites/ostp/PCAST/pcast_forensic_science_report_final.pdf">PCAST</a>) in the US found that only two properly designed studies of latent fingerprint analysis had been conducted. These both found the rate of false matches (known as “false positives”) to be very high: <a href="https://www.ncjrs.gov/pdffiles1/nij/grants/248534.pdf">1 in 18</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/21518906">1 in 30</a>. </p>
<p>One of the main reasons for these high error rates is that fingerprint analysis involves human judgement, and relies on a methodology (known as “ACE-V”) that is <a href="http://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=7201&context=jclc">not sufficient</a> to ensure the accuracy and reliability of an examiner’s conclusions. This means there is no guarantee that two different examiners who follow its steps will reach the same result. </p>
<h2>Recent improvements</h2>
<p>Since the National Research Council report was released, scientists have <a href="https://obamawhitehouse.archives.gov/sites/default/files/microsites/ostp/PCAST/pcast_forensic_science_report_final.pdf">worked hard to prove</a> that fingerprint examination is scientific. </p>
<p><a href="https://www.aaas.org/report/latent-fingerprint-examination">Research</a> has now convincingly established that the ridge patterns on fingers vary greatly among individuals, and that there is little variation in a person’s fingerprints over time. This provides a scientific basis for using fingerprints to distinguish individuals, even identical twins. </p>
<p>But there is still <a href="https://www.aaas.org/report/latent-fingerprint-examination">no scientific basis</a> for concluding that a print must have been left by a specific person, or even for estimating the number of people who might be the source of a print. </p>
<p>The most that can be said is that two prints have many corresponding features, with no differences that would indicate they were made by different fingers. It may also be possible for an examiner to say that the set of features found in the prints is unusual.</p>
<h2>Cognitive bias</h2>
<p>Because fingerprint analysis depends heavily on human judgement, an examiner’s conclusions may be improperly influenced by non-scientific factors, such as <a href="https://www.nist.gov/publications/latent-print-examination-and-human-factors-improving-practice-through-systems-approach">irrelevant contextual information</a>. </p>
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Read more:
<a href="https://theconversation.com/explainer-how-law-enforcement-decodes-your-photos-78828">Explainer: how law enforcement decodes your photos</a>
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<p>This phenomenon, which is known as “<a href="https://www.journals.elsevier.com/journal-of-applied-research-in-memory-and-cognition/target-articles/forensic-confirmation-bias-problems-perspectives">cognitive bias</a>”, has been demonstrated in various studies. </p>
<p>In <a href="http://www.sciencedirect.com/science/article/pii/S0379073805005876">one study</a>, five fingerprint experts were told they were comparing Brandon Mayfield’s fingerprint with the fingerprint found in Madrid. They were asked whether they would also have (wrongly) found a match. </p>
<p>In reality, the experts were given fingerprints from a different case they had personally found to match years earlier, in the normal course of their casework. Four of the five experts changed their opinion. This was seen to be due to their expectation that the fingerprints did not match.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/22212067">Another study</a> found that fingerprint examiners can be improperly influenced by the use of automated fingerprint identification systems, which provide ordered lists of the most likely matches. </p>
<p>The study found that examiners are more likely to wrongly identify one of the prints near the top of the list as a match, and to fail to make correct identifications if the print is down low on the list.</p>
<h2>Implications</h2>
<p>While these reports and studies indicate a need for caution when relying on fingerprint examinations, they do not mean that police should stop using fingerprints. </p>
<p>Fingerprinting is an essential tool for investigating crime, and should continue to be used for this purpose. But steps need to be taken to limit the likelihood of future miscarriages of justice.</p>
<p>Everyone in the system has a role to play. Scientists need to conduct <a href="https://www.aaas.org/report/latent-fingerprint-examination">further research under realistic conditions</a>. </p>
<p>Police forces must <a href="https://www.justice.gov/archives/ncfs/page/file/641676/download">take steps</a> to minimise the risks of cognitive bias. For example, they should use <a href="https://www.ncbi.nlm.nih.gov/pubmed/23601722">context management procedures</a> to avoid exposing examiners to unnecessary contextual information. </p>
<p>Lawyers and judges must make sure that only scientifically valid opinions are <a href="http://law.unimelb.edu.au/__data/assets/pdf_file/0011/2494325/04-Edmond.pdf">given in court</a>, and that the value of fingerprint evidence is not overstated. Fingerprint examiners should make it clear that they are <a href="https://www.webarchive.org.uk/wayback/archive/20150428160106/http:/www.thefingerprintinquiryscotland.org.uk/inquiry/files/TheFingerprintInquiryReport_High_res.pdf">expressing an opinion and not a fact</a>. </p>
<p>And everyone should acknowledge that errors do occur in fingerprinting analysis, and have happened in the past.</p><img src="https://counter.theconversation.com/content/85534/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jamie Walvisch does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Fingerprinting is a valuable police tool for tracking down suspects, but it’s not perfect. However, we can reduce the risk of any mistaken identity if we work within the limits of fingerprinting.Jamie Walvisch, Lecturer, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/822132017-08-17T20:21:02Z2017-08-17T20:21:02ZFor sniffing out crime and missing persons, science backs blood-detection dogs<figure><img src="https://images.theconversation.com/files/182171/original/file-20170816-6110-t1pd6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dogs can reliably sniff out human blood, even after two years of environmental degradation. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-australian-shepard-nose-sniffing-543831754?src=EJbDmO5lo2BehoFg2ke08A-1-50">Jason Korbol/shutterstock</a></span></figcaption></figure><p>It’s difficult to contemplate the tragedy of losing a loved one and never knowing what happened to them. </p>
<p>Every year, an estimated <a href="https://www.missingpersons.gov.au/view-all-profiles">38,000 people go missing</a> in Australia. While almost 95% of these individuals are found relatively quickly, <a href="https://www.missingpersons.gov.au/view-all-profiles">5% become long-term missing persons cases</a>, with many suspected victims of foul play.</p>
<p>British toddler Madeleine McCann <a href="https://www.theguardian.com/uk-news/2017/apr/30/madeleine-mccann-disappearance-parents-still-hope-10th-anniversary">disappeared in 2007</a> on a family holiday in Portugal, and has never been found. <a href="http://www.telegraph.co.uk/news/uknews/1560443/Madeleine-sniffer-dogs-detect-scent-of-body.html">Sniffer dogs</a> in this case initially assisted in locating blood samples found in the holiday home. </p>
<p>However, the use of canines has attracted <a href="http://www.telegraph.co.uk/news/uknews/1560443/Madeleine-sniffer-dogs-detect-scent-of-body.html">controversy</a> due to <a href="http://www.dailymail.co.uk/news/article-482105/Madeleine-McCanns-consult-American-lawyers-cadaver-dog-evidence.html">misunderstandings about the sensitivity of dogs</a> to reliably find evidence through scent at a crime scene. </p>
<p>But our recent research shows that for sniffing out blood, dogs are one of the best investigative screening tools for expediting crime scene searches. </p>
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<p><em><strong>Read more:</strong> <a href="https://theconversation.com/explainer-whats-actually-in-our-blood-75066">Explainer: what’s actually in our blood?</a></em> </p>
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<h2>Blood is important evidence</h2>
<p>Locating blood at a crime scene is a vital step. It can assist in recreating the events of a crime, identifying victims or suspects, establishing secondary crime scenes, ascertaining potential murder weapons, and in identifying links between individuals with locations and objects. </p>
<p>The police employ various testing methods when processing a crime scene for blood evidence. Colour and chemical change tests are applied to indicate the possible presence of blood. A common example is luminol, which emits a bright blue colour when it reacts with haemoglobin (a molecule found in blood). </p>
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<img alt="" src="https://images.theconversation.com/files/182172/original/file-20170816-22170-1fndjrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182172/original/file-20170816-22170-1fndjrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182172/original/file-20170816-22170-1fndjrr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182172/original/file-20170816-22170-1fndjrr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182172/original/file-20170816-22170-1fndjrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182172/original/file-20170816-22170-1fndjrr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182172/original/file-20170816-22170-1fndjrr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Luminol creates a blue glow when it reacts with haemoglobin, one of the molecules found in blood.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/evidence-footprint-on-place-crime-bathroom-522250081?src=j-HnKUSKCIHrewXQKKNHNw-1-4">Couperfield/shutterstock</a></span>
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<p>If positive results are achieved, areas of interest are then targeted for further processing with more specific tests to confirm the presence of human blood.</p>
<p>But the smell of blood can also be used to locate it at crime scenes. In recent years, several law enforcement agencies in Europe and Australia have introduced blood-detection dogs, which are trained specifically for blood evidence. </p>
<p>By using this distinct dog unit, a large search area can be screened as a potential crime scene in cases of assault, missing persons, mass disasters or suspected homicides where a body may not be present. </p>
<p>Blood-detection dogs are a recently specialised unit under a broader grouping of scent-detection dogs used by law enforcement. The dogs’ highly sensitive sense of smell can locate a range of target odours including drugs, explosives, human bodies (known as “cadavers”) and now blood. </p>
<h2>The odour of death</h2>
<p>Forensic odour profiling aims to unravel the chemical components of odour. Our research in this area focuses on the individual odour-producing constituents of blood, and explore how environmental changes can affect the ability of blood-detection dogs to detect these. </p>
<p>A scientific analysis of scent involves collecting the gases emitted from blood samples, and then separating the gaseous odour molecules (known as volatile organic compounds) to be individually detected and identified at trace levels. </p>
<p>Often searches are carried out a considerable time after the crime occurred. So in our first studies we compared the odour of fresh and degraded blood, chemically profiled over a two-year study and presented to cadaver-detection and blood-detection dogs in training. Degraded blood is defined as blood which has undergone decomposition through the breakdown of cellular material. </p>
<p><a href="https://link.springer.com/article/10.1007/s00216-016-9748-9">Preliminary results</a> indicate that a distinct odour change occurs from blood collected within 48 hours to degraded, with the odour profile changing throughout the degradation process. Impressively, the canines which were mostly trained on fresh blood could locate blood confidently up to six months old, and had the ability to locate blood even as old as 24 months.</p>
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<p><em><strong>Read more:</strong> <a href="https://theconversation.com/how-science-is-helping-the-police-search-for-bodies-in-water-73931">How science is helping the police search for bodies in the water</a></em> </p>
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<p>We’ve also established through this research that the <a href="https://link.springer.com/article/10.1007/s00216-016-9748-9">surface on which the blood is deposited affects the odour produced by the blood</a>. Blood left on porous surfaces (such as clothing) and blood on non-porous surfaces (such as metallic objects) produce unique odour profile patterns which are most apparent when the blood is freshly deposited. </p>
<p>It’s important that blood-detection dogs are trained to reliably locate blood on any type of crime scene surface they could potentially encounter on the job.</p>
<h2>Blood is blood</h2>
<p>A comparison of blood donors has also expanded our understanding of what human blood actually smells like: we refer to this as the “core odour profile of blood”. Although much of the odour profile is consistent from individual to individual, some variations do occur linked with differing lifestyle, diet, health and other factors in the environment. </p>
<p>However, early results suggests this may have little effect on the canine’s ability to locate fresh and degraded blood from different people.</p>
<hr>
<p><em><strong>Read more:</strong> <a href="https://theconversation.com/spilling-blood-in-art-a-tale-of-tampons-trump-and-taboos-81455">Spilling blood in art, a tale of tampons, Trump and taboos</a></em> </p>
<hr>
<p>We also compared the sensitivity of detecting latent blood – that is, blood that is invisible to the naked eye – by dogs as compared to other methods such as luminol. </p>
<p>We created an artificial scenario in which a suspect attempted to remove a victim’s blood from clothing by washing it five times. Initial results indicate that the blood-detection and cadaver-detection dogs are much more sensitive than our current analytical detection approaches, but complementary to the use of luminol. </p>
<h2>What happens to bodies after death</h2>
<p>Our research into blood-detection by dogs is part of a broader program in forensic odour profiling and the science of body decomposition. </p>
<p>The first Australian Facility for Taphonomic Experimental Research (or AFTER) is now established. Collaborating with 13 partner organisations, ongoing research at this facility strengthens our understanding of how the human body decomposes, and ultimately will assist investigators in the search for human remains.</p>
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<figcaption><span class="caption">The Australian Facility For Taphonomic Experimental Research (AFTER) examines how bodies decompose under Australian conditions.</span></figcaption>
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<p>By investigating the odour profile of common training aids utilised by law enforcement we can provide important recommendations for the training of blood-detection and cadaver-detection dogs to ensure their success in the field.</p>
<p>Establishing a connection between science and law enforcement, we work hand in paw to provide justice for victims and bring closure for their families.</p><img src="https://counter.theconversation.com/content/82213/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>LaTara Rust receives funding from the Australian Government Research Training Program Scholarship and the Australian Research Council (ARC).</span></em></p><p class="fine-print"><em><span>Shari Forbes receives funding from the Australian Research Council and USAID.</span></em></p>Blood-detection dogs work paw in hand with scientists and Australia’s police to solve crimes and missing persons cases.LaTara Rust, PhD candidate, University of Technology SydneyShari Forbes, Professor , University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/685492016-11-14T14:34:35Z2016-11-14T14:34:35ZWhy CSI: Space will be a far greater challenge than forensic science on Earth<figure><img src="https://images.theconversation.com/files/145808/original/image-20161114-5101-m1z8c2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">ESA</span></span></figcaption></figure><p>At the Hawaii Space Exploration Analog and Simulation centre, NASA has just concluded the latest year-long study into the <a href="http://hawaiitribune-herald.com/news/local-news/hi-seas-one-year-later">effects of long-term isolation in space</a>. The research is primarily focused on examining psychological and psycho-social factors that will help NASA draw up the highly effective teams needed for <a href="http://news.nationalgeographic.com/2016/08/nasa-mars-hi-seas-hawaii-human-mission-space-science">long-duration space exploration missions</a>. And among the behaviours studied is how aggression and violence might arise among space crews during long space voyages.</p>
<p>Crime and punishment are among the <a href="https://books.google.co.uk/books?id=njN1CQAAQBAJ&dq">oldest problems faced by mankind</a>. Immoral or illegal conduct has been a fixture in human history from the dawn of civilisation to the space age we live in today. It’s inevitable that it will at some point become an issue in space, so it’s important to be <a href="https://www.researchgate.net/publication/228227432_Jurisdiction_in_Outer_Space_Challenges_of_Private_Individuals_in_Space">prepared for the eventuality</a>. The question is how, or whether, terrestrial methods of inflicting violence can be used in space, and if so, whether terrestrial methods of criminal investigation are up to the job. </p>
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<a href="https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145814/original/image-20161114-5087-1veaslv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The TP-82 combination shotgun, pistol and machete carried by cosmonauts until 2006.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:TP-82.jpg">Chris Browning/GunNewsDaily.com</a></span>
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</figure>
<p>It’s thought that it is possible to <a href="http://www.livescience.com/18588-shoot-gun-space.html">fire handguns in space</a>, and of course sharp stabbing or cutting weapons would work as they do on Earth, as would poisoning or attacks with bare hands. Astronauts have <a href="http://gizmodo.com/the-ultimate-list-of-weapons-astronauts-have-carried-in-1768199454">carried weapons on board space vessels</a> since humanity first ventured into space.</p>
<p>There’s also the risk of tampering with or sabotage of the highly sensitive <a href="http://www.nasa.gov/content/robotics-science-and-spacesuit-tests-aboard-station">personal life support equipment</a> and <a href="https://www.nasa.gov/sites/default/files/104840main_eclss.pdf">living quarters, laboratory and observatory facilities</a> on board spacecraft. The survival of any spacecraft crew depends entirely on maintaining a habitable environment – if for some reason the cabin should depressurise, the <a href="http://www.bbc.com/future/story/20160617-why-your-blood-would-boil-in-space">astronauts’ blood would boil and turn to a gas</a>. Malfunctions are not unheard of either – water leaks inside astronaut’s suits while outside the spacecraft have occurred on <a href="http://www.space.com/31635-water-leak-astronaut-helmet-halts-spacewalk.html">more than one occasion</a>, and <a href="http://www.airspacemag.com/space/spacewalk-almost-killed-him-180950135/">could have been fatal</a>.</p>
<p>Space is a harsh enough environment as it is without any human malfeasance. Astronauts must contend with dangers from <a href="http://www.space.com/11083-hubble-photo-dying-star-toxic-gas.html">toxic gases released by dying stars</a> and radiation levels that can cause <a href="http://observer.com/2016/07/space-radiation-devastated-the-lives-of-apollo-astronauts">cardiovascular diseases</a>, to exposure to bacterial strains which can grow at <a href="http://www.popsci.com/science/article/2009-11/mutant-bacteria-are-likely-threaten-future-space-travelers">twice the rate as on Earth</a>. So we need to be able to distinguish between these natural effects and conduct that would be regarded as criminal on Earth.</p>
<h2>CSI: Space</h2>
<p>Crime scene examination is a <a href="https://books.google.co.uk/books?id=tbvAjIt4k0cC&dq">joint scientific and investigative endeavour</a> which requires investigators to assess crime scenes and other locations, identify evidence and use it to <a href="https://books.google.co.uk/books?id=DQtvZVk929QC&dq">piece together what happened</a>. In space, investigators must rely on not just forensic principles but also elements of astrophysics, chemistry and biology — because it’s all very different out there.</p>
<p>For example, biological samples such as blood, semen and other fluids are significant for forensic investigations. Tests have confirmed that <a href="https://www.scientificamerican.com/article/dna-can-survive-reentry-from-space">DNA can survive in space</a> for a limited time, and within habitable vessels and planetary settlements NASA has demonstrated the <a href="http://www.nasa.gov/mission_pages/station/research/news/dna_sequencing">possibility of DNA sequencing</a>. The vast amount of solar radiation is problematic, as fluids will lose heat rapidly in low or zero air pressure, freeze, and evaporate. </p>
<p>In enclosed locations, sweat can be expelled from crew-members and <a href="https://www.washingtonpost.com/news/morning-mix/wp/2014/06/10/astronauts-well-kept-secret-space-has-a-smell">flung onto walls and equipment</a> if they are moving due to weightlessness in space. If this sweat can be recovered before the condensate system <a href="http://www.nasa.gov/vision/space/livinginspace/eclss1.html">recycles it into drinking water</a>, it can be used as a <a href="http://www.nij.gov/topics/forensics/evidence/dna/basics/pages/identifying-to-transporting.aspx">source of DNA</a>.</p>
<h2>Blood spatter analysis</h2>
<p>In microgravity liquids ball up and float around, restrained only by their <a href="http://nasaphysics.cet.edu/microgravity.html">surface tension</a>, and blood pressure decreases resulting in <a href="https://science.nasa.gov/science-news/science-at-nasa/2001/ast02aug_1">loss of around a fifth of blood volume</a>. If a crew-member’s body is cut, the physics of space would not allow for the same blood spatter patterns as seen on Earth. The likelihood is that blood would form spherical shapes like other liquids, either sticking to the victim or floating away from their source. </p>
<p>Reconstructing a crime scene from spatter pattern analysis would be incredibly complicated. The current <a href="https://www.wired.com/2012/07/st_equation_bloodspatter">mathematical equation</a> used for such analysis would need changing to account for gravitational difference, and even then it would be of little reliability due to the fluid dynamics of space.</p>
<h2>Ballistics</h2>
<p>A gunshot fired in space would in all likelihood kill not merely from the impact of the bullet but the damage it would cause to someone’s space suit. With no air resistance or gravity, the ammunition’s casing expelled from the weapon would float away at speed, potentially a hazard itself. Fired at close quarters inside a spacecraft, a bullet could pass through a human body, through any bulkhead walls and continue to travel for vast distances through space. Without casing or bullet, it would be difficult to produce any useful ballistic analysis.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/145816/original/image-20161114-5101-14rzzci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145816/original/image-20161114-5101-14rzzci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145816/original/image-20161114-5101-14rzzci.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145816/original/image-20161114-5101-14rzzci.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145816/original/image-20161114-5101-14rzzci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145816/original/image-20161114-5101-14rzzci.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145816/original/image-20161114-5101-14rzzci.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dusting for fingerprints would probably not work in space.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/westmidlandspolice/7131876629">westmidlandspolice</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Fingerprint Evidence</h2>
<p>Fingerprinting uses carbon or metal-based powders which stick to the moisture of prints left on physical surfaces, or through a method called <a href="https://www.gov.uk/government/publications/fingerprint-source-book">superglue fuming</a> where cyanoacrylate is heated in a container, and the resultant fumes bond with fingerprints on objects placed inside a enclosed container. Space physics means a method requiring enclosed spaces wouldn’t be a viable solution in a spacecraft, while a phenomenon called <a href="http://onlinelibrary.wiley.com/doi/10.1002/aic.690471209/abstract">particle agglomeration</a>, where particles such as dusting powder stick together, could render dusting techniques hard to implement in microgravity. One alternative is to replace dusting altogether and use <a href="https://www.newscientist.com/article/dn12931-laser-fingerprint-scanner-does-away-with-dusting/">laser scanning</a> for fingerprinting.</p>
<h2>Trace evidence and toxicology</h2>
<p>Assuming environmental factors don’t make collection and storage unworkable, trace evidence can be analysed inside space laboratories equipped with <a href="http://www.laboratorynetwork.com/doc/mini-mass-spectrometer-boards-international-s-0001">mass spectrometry equipment</a>, already used on remote stations, which can also be used to analyse <a href="http://education.seattlepi.com/mass-spectroscopy-used-forensic-science-6611.html">poisons and toxins</a>.</p>
<p>However, what these problems and their solutions require is real-world testing in space conditions. NASA has used the language of crime scene investigations in interesting education programmes, which approach the creation and expansion of the universe in terms of “space forensics” or as a <a href="https://pcos.gsfc.nasa.gov/epo%5D(https://pcos.gsfc.nasa.gov/epo">“crime scene”</a>. But there has been little actual research into the use of forensic science in space. NASA’s 2002 <a href="http://www.fsijournal.org/article/S0379-0738(02)00079-8/abstract">collaboration with the US National Institute of Justice</a> to explore the use of space technology in Earth crime scenes was encouraging but the real focus should be on how forensic science from Earth would be implemented in space.</p><img src="https://counter.theconversation.com/content/68549/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mehzeb Chowdhury does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Using terrestrial forensic science to point the finger of blame to criminals in space will be much harder than it looks.Mehzeb Chowdhury, PhD Researcher in Forensic Science and Criminal Investigations, Durham UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/649272016-09-12T07:49:37Z2016-09-12T07:49:37ZThis new fingerprint technique could revolutionise the way we solve gun crime<figure><img src="https://images.theconversation.com/files/136633/original/image-20160905-4784-nhp1hf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hidden clues.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=FVYJcafC7VEahRT_0kKwzg-1-68&id=159828569&size=medium_jpg">Shutterstock</a></span></figcaption></figure><p>Despite the development of DNA profiling for criminal investigation, fingerprints remain the most common type of forensic evidence to be recovered from a crime scene. From the first identifications made at Scotland Yard in the early years of the 20th century, to the computerised storage and searching that is available now, the <a href="http://www.onin.com/fp/fphistory.html">basic concept of making a fingerprint identification has not changed</a>. Imperfections (or minutiae) in the pattern of ridge lines on the tips of fingers and on the palms provide the key to linking a fingerprint found at a crime scene (often referred to as a finger mark) to the fingerprint of an individual. </p>
<p>Since its inception, many techniques have evolved to reveal finger marks, usually deposited in sweat, at the crime scene. Some, such as the use of a fine powder applied with a brush, are as old as fingerprinting itself and remain in use because they are simple and easy to use, and are effective at revealing invisible (or latent) finger marks. Today, the numerous techniques available are neatly summarised by the Home Office Centre for Applied Science and Technology in their <a href="https://www.gov.uk/government/publications/fingerprint-source-book">Fingerprint Source Book</a>, which is essential reading for any crime scene investigator.</p>
<p>Generally, finger mark recovery techniques are arranged by reference to the surface (or substrate) on which the latent finger mark is deposited, with some substrates being historically problematic for latent finger mark recovery. One such substrate is the outer surface of spent brass shell casings, usually ejected from a firearm after firing. </p>
<p>Often, at the scene of a crime involving the discharge of a fireman, these spent shell casings present the only physical evidence left by the offender, so their importance shouldn’t be underestimated. Latent finger mark recovery from spent shell casings is difficult as the area of contact between the finger and the casing is limited due to the curvature of the casing and also because of the environmental extremes undergone by the casing during firing and ejection, which can all but obliterate latent finger marks. </p>
<h2>Solving the mystery</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/137071/original/image-20160908-25244-s3li0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/137071/original/image-20160908-25244-s3li0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/137071/original/image-20160908-25244-s3li0e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/137071/original/image-20160908-25244-s3li0e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/137071/original/image-20160908-25244-s3li0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=514&fit=crop&dpr=1 754w, https://images.theconversation.com/files/137071/original/image-20160908-25244-s3li0e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=514&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/137071/original/image-20160908-25244-s3li0e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=514&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shell casings are notoriously difficult to fingerprint.</span>
</figcaption>
</figure>
<p>Following a serendipitous finding by researchers at Swansea University that rubbing a metal surface with a tissue does not necessarily remove the finger mark ridge minutiae, we started to investigate why this might be so – and, importantly, how the finger mark might be revealed. Through experimentation, <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1556-4029.2008.00738.x/abstract">we were able to show</a> that the inorganic components present in fingerprint sweat, particularly chloride ions, were able to induce corrosion on the metal surface at the location of the finger mark deposit. Further, this corrosion was quite difficult to remove and remained even after washing the metal in warm soapy water to remove any trace of the original sweat deposit. </p>
<p>Copper and its alloys (such as brass) were found to be very easily corroded by fingerprint sweat, which, potentially, makes this useful for finger mark recovery from spent brass shell casings. After further experimentation, <a href="http://iopscience.iop.org/article/10.1088/0022-3727/41/12/125502/pdf">a technique was devised</a> that enabled a fine coloured powder to adhere preferentially to areas of corrosion on a brass disk, to which had been applied a large (about 2,500 V) electric potential. </p>
<p>This <a href="http://scitation.aip.org.ezproxy4.lib.le.ac.uk/content/aip/journal/rsi/80/7/10.1063/1.3183578">powder adherence</a> was developed to work with round brass shell casings, rather than a flat disk, and eventually <a href="http://www.consoliteforensics.com/">commercialised</a>.</p>
<h2>What now?</h2>
<p>As might be expected, the main market for such technology lies outside the UK and since its development, has been used in many criminal cases, mainly in the US, to try and recover finger mark corrosion from spent brass shell casings. One positive aspect is that, because the corrosion is difficult to remove from the brass, the technique can be applied to casings that are many years old and relate to what are termed “cold cases”. Fortunately, law enforcement agencies rarely destroy evidence – particularly from unsolved homicides – and these offences present ideal evidence for this technique. </p>
<p>In 2015, the University of Leicester signed an agreement with Zhejiang Police College in China to collaborate in advancing forensic science research and teaching. An early result of this has been the joint development of an improvement in the way this technique works. Essentially, the electrically charged shell casing is now rotated in a bed of the powder, which makes the process easier than the original method of applying the powder directly to the casing. </p>
<p>Why is this new development important? Well, as finger mark visualisation techniques that are quick, easy and effective are preferred, anything that makes the process easier to produce a positive result is to be welcomed. As the use of firearms in crime seems unlikely to diminish, this development offers law enforcement agencies a further opportunity to crack cases.</p><img src="https://counter.theconversation.com/content/64927/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John W Bond does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It could even help crack long-forgotten cold cases.John W Bond, Senior Lecturer in Criminology, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.