The AFP’s world-class forensic capability will be on show this week to celebrate National Science Week 2022.
AFP Forensics comprises a large number of specialist services and capabilities at the AFP’s state-of-the-art forensics facility in Canberra and within the AFP’s regional commands.
AFP Forensics’ specialties include: biometrics including DNA, fingerprint comparison and facial identification, chemical criminalistics, digital, audio and video forensics, crime scene investigation, document examination, firearms and ballistics, post-blast analysis and disaster victim identification amongst others.
National Science Week 2022 runs from 13-21 August and is Australia’s annual celebration of science and technology. This year’s theme is Glass: More than meets the eye, celebrating the many roles glass plays in our lives.
AFP forensic investigators commonly work with glass, whether it be examining glass fragments collected from a crime scene, undertaking glass comparisons using a range of instrumentation, or through the glass lenses present in photography, magnification or microscopy to examine minute particles, compare handwriting samples or take crime scene photographs.
AFP Forensic Chemist Dr Jo Bunford said glass was a common type of evidence found at crime scenes.
“Glass is common in the everyday world but can become important evidence when broken in the commission of crimes such as break-ins, hit and run, ram raids, vandalism and assaults,” Dr Bunford said.
“Types of glass that may be seen in forensic casework can include fragments from door and window panes, vehicle windows and windscreens, bottles and containers, and television and mobile phone screens.”
When a pane of glass is broken, much of it falls in the direction of the blow that causes it to break, however, a large number of small fragments can travel backwards towards the breaker of the glass and become lodged in hair and clothing, or on what was used to break the glass.
“Glass fragments can be retained on clothing items, in hair and on the item used to break the glass for a number of hours after transfer. It is this knowledge of glass transfer and persistence that a forensic scientist can utilise to assist investigators,” Dr Bunford said.
“The presence of freshly broken glass fragments on clothing, in hair and on items used to break glass can indicate a recent contact with broken glass enabling a timeframe to be implied for when the glass was broken.”
The known physical and chemical properties of glass can be used by the forensic scientist to compared fragments recovered from clothing and other items of interest to a known glass sample from a scene. For example, recovered fragments compared to a broken window can provide a connection between people and locations/objects.
One example of this was an alleged hit and run of a cyclist and pedestrian in Canberra, where the suspect’s vehicle was recovered by police with severe damage to the windscreen.
The clothing of the cyclist, pedestrian and alleged driver were all examined for glass fragments and compared to samples from the damaged windscreen which were found to be a match.