Who did it? How? When? These are the types of questions that forensic scientists ask.
Who did not do it? How can we be sure? What’s the evidence? What are the probabilities? Beyond reasonable doubt? Is it verifiable? Will other experts in the same field interpret the data the same way? Will experts from different fields, using different data, come to the same or conflicting conclusions? Beyond reasonable doubt? Will truth win out and will a perpetrator be brought to justice?
The questions of forensic scientists, framed within legal contexts, are similar to questions that scientists everywhere ask. ‘Working scientifically’ – clarifying and challenging, looking for patterns and meanings, making and judging observations, examining and evaluating, summarising and reporting – these are what chemists and physicists and biologists – all scientists – do.
Forensic science draws on, and brings together, many scientific disciplines. Chemical tests, identification of hair, blood, dirt, cloth fibres – DNA testing, microscopy, spectroscopic analysis, forensic psychology and forensic medicine – all contribute to integrated analysis of a crime and the physical evidence left at a crime scene. While forensic science has been a feature of many schools’ senior multi-strand science, it can also be a real-life context for learning in the other senior sciences – and it can certainly be a stimulating and life-like context for learning science in all the years of schooling.
A forensic scientist may perform the following tasks:
- identify illicit drugs
- analyse drugs and poisons in human tissue and body fluids including blood alcohol results
- examine and compare materials such as fibres, paints, cosmetics, oils, petrol, plastics, glass, metals, soils and gunshot residues
- examine items of human and animal biological material to be compared with victims and suspects using DNA profiling
- conduct botanical identification of plant materials at trace levels, and whole-plant identification such as cannabis
- conduct document examinations, both physical (e.g. handwriting, typewriting) and chemical (e.g. analysis of inks and papers)
- examine crime scenes
- identify firearms and ammunition (forensic ballistics)
- detect, enhance, recover and identify latent fingerprints, footprints, tool marks, shoe marks, tyre marks and tracks
- examine fire and explosion scenes to establish the origin and cause
- enhance and analyse audio recordings
- produce reports, appear in court and present scientific and/or opinion testimony accurately and in a manner which is readily understood by the court
- make presentations to a wide variety of audiences on the work of forensic scientists
- liaise with, and provide advice to, police investigators, scientists and pathologists across a broad range of disciplines.
A wide range of expertise is required in forensic investigations. A forensic scientist may specialise in chemistry, physics, biochemistry, molecular biology, botany, geology, metallurgy, pharmacology, toxicology, crime scene examination, firearms examination, fingerprint and document examination.
Every criminal leaves behind evidence. It is the job of the Clinical Forensic Medicine Unit to find that evidence which often is not visible to the human eye – traces of skin, clothing, blood, hair and chemical substances.
These Police experts conduct medical analysis of crime scenes, injuries, and pharmacological and toxicological materials and assist on a wide range of matters concerning forensic evidence.
Unit services include:
- Medical analysis of injured offenders and victims
- Medico-legal opinions
- Evaluating material relevant to alcohol, drugs and traffic safety.
The Unit also:
- Assists coronial inquiries
- Provides expert medical evidence in court
- Researches issues of drug, alcohol and traffic safety
- Conducts research to maintain up to date knowledge of the many facets of drug and alcohol pharmacology.
The Clinical Forensic Medicine Unit employs 3 specialists and a scientist in forensic medicine.
Clinical Forensic Medicine Unit: Level 4, Sydney Police Centre, 151 Goulburn St, Surry Hills NSW 2010.