A serious criminal investigation without forensic science seems unthinkable. turkguy0319

Explainer: Forensic science

Ian Dadour

FORENSICS AUSTRALIA – There has always been a role for forensic science in criminal investigations, but these days, with criminals committing clever, well thought-out crimes more often, it’s now an essential tool for criminal investigations.

Without question, the field of forensic science has come a very long way since its recorded beginnings around 700AD, when the Chinese used fingerprints to establish the identity of documents and clay sculptures, thereby identifying their authenticity.

Since that time, some notable discoveries have occurred – such as the use of chemistry to analyse myriad inks, drugs and minerals and the more recent discovery of DNA which has become a mainstay tool for identifying perpetrators and excluding the innocent.

There are three core disciplines that constitute forensic science – medicine, chemistry and anthropology – followed by an extensive array of sub-disciplines.

These include:

When a crime is committed and the forensic team is called in, there are many experts who cover their specialised fields. Although all these people could be considered forensic scientists, they have different skills and focuses.

The minimum requirements for a criminal investigation are:

1) Field officers: these are technicians who visit the crime scene and collect physical evidence that may be related to the crime.

They also document and record the scene by taking photographs and videos.

2) Lab officers: these are technicians who analyse and complete tests on the evidence collected by field officers.

Sometimes the above two roles are further broken down into expert areas, including:

They also look for any alterations that may have occurred to original documents and may be asked to determine whether a particular copier or typewriter has been used in the creation of a document.

These people are responsible for analysing and comparing hair, fibres, glass, soil and paints to work out type and origin.

While the above roles relate to all crimes, there are some additional experts who are called upon if the crime involves finding a body. The roles specifically relating to examining remains or murders are:

They might also examine living victims to determine the cause and age of injuries received during the crime.

They use autopsy reports, police reports, medical records, suspect or witness interviews and the results of crime lab evidence analyses in the pursuit of answers.

These experts use skeletal remains to work out the age, sex and race of the deceased.

They can also identify any injuries or illnesses the victim may have suffered, and can sometimes even establish the time of death.

Forensic anthropologists can also perform toxicological, chemical and DNA tests on remains to discover more about the victim.

They can also find out a lot by visiting the location where the remains were found.

They are also called in for cases in which bite marks or teeth are found.

It’s common for bodies that have been found sometime after death to be invaded by insects.

Forensic entomologists can also use their knowledge of where different insects live to work out if a body has been moved or not.

Key strengths

Observational skills are important for all forensic scientists, of course, as is the ability to be methodical and accurate at all times.

Scepticism is another important quality, particularly when investigating crimes. There are a couple of key things to remember:

A witness may state they saw a woman leaving the crime scene. But what if it was a man with long brown hair?

Variations on this easily-made mistake are endless and could lead to all sorts of complications.

It’s the forensic scientist’s job to make sure it doesn’t – to get the job done, and done correctly.

This is part one of The Conversation’s Forensics Australia series. Meet the people behind the science in parts two to five.

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Ian Dadour receives funding from UWA.

University of Western Australia provides funding as a founding partner of The Conversation AU.