Could common spices like turmeric, cinnamon and paprika be used instead of traditional black carbon powders in detecting fingerprints from crime scenes?
Despite being used by forensic investigators for decades, carbon powders can be hazardous and expensive – often using ferrous oxide and other metallic compounds to create a fine black powder that investigators use to dust for prints.
Common spices are cheaper and more readily available, prompting Masters of Forensics student Renee Ang to test their suitability as fingerprint enhancement agents.
And, despite decades of anecdotal evidence suggesting that DNA can never be recovered from a fired bullet, can it be achieved through a controlled experiment?
Like Ang, fellow Masters student Nick Booth spent a semester testing whether more rigorous forensic evidence-gathering methods can be applied to improve the chances of overcoming these age-old problems.
In Booth’s case, he dosed .22 calibre hollow point ammunition with a known quantity of DNA and evaluated it for DNA recovery after being fired by Murdoch’s Whitby Falls Farm manager Bob Fawcett.
What he found was, despite little evidence historically that DNA survives on a bullet after being fired, that tiny levels of detectable DNA were detected on bullet fragments during the experiment.
Lecturer in Forensic Science Brendan Chapman said Booth’s experiment was the first known and controlled instance whereby detectable DNA had survived after a firearm was discharged.
DNA recovered on bullets after firing
“Current anecdotal thought is that DNA doesn’t survive the extreme heat, pressure and mechanical forces generated by the cycle of firing,” Chapman said. This suggests that this study is the first noted example of this in a controlled experiment.”
The Murdoch Masters student adapted a novel method published by a team at Leiden University in the Netherlands. Volunteer DNA was placed at the tip of the .22 calibre bullets in the divet created by the hollow point design.
Bullets were shot into a device housing an A3 ream of paper to “collect" the bullet and its fragments were removed for DNA sampling.
“We know that some DNA survived the firing process, but now more work is needed to confirm that the surviving DNA is consistent with the DNA profile of our volunteer.
Thirteen Master of Forensics student presented their findings on Monday, including Renee Ang, who found that paprika was not likely to replace traditional black carbon powder when collecting fingerprints for examination any time soon.
However, tumeric and cinnamon were almost as good as as black fingerprint powder and their differing contrasts could be useful especially in the collection of sebaceous – or oily – fingerprint deposits.
“If nothing else, this novel approach to detecting fingerprints could be very useful and readily available in the teaching of forensics gathering in schools,” Chapman said.
In another novel approach which investigated the investigators, Elizabeth Morahan tested “wearables” for the monitoring of physiological indicators of stress in crime scene officers.
“Homicide crime scenes are a fast paced, highly stressful working environment whereby officers are subjected to long work hours in sub-optimal work environments,” Chapman said. “The added traumatic nature and pursuit of justice for the victims makes for a highly stressful work environment that hasn’t been studied before.”
Wearable GPS tracking devices such as FitBits are a booming trend, especially in the elite sports industry, who use activity and physiological metrics to track athletes in enhancing performance.
“Our question, was ‘why not apply the same monitoring to forensic investigators to ensure they are performing at peak,” Chapman said. “We monitored heart rate, blood pressure, body temperature and saturated oxygen levels to see if the activity had a physiological effect on two candidates.
“Decision-making skills at a crime scene are imperative to ensure that no evidence goes overlooked and that justice is served. Stress has effects on cognition and high stress levels may lead to poor judgement or oversights in critical decisions.”
Mr Chapman said the Masters students had shown that novel ways of testing forensics evidence could be used on the ground to improve the accuracy and performance of crime scene investigators.
He said WA Police had shown some interest in the use of wearable technologies in assessing stress and activity levels in forensics personnel.
The students will present their findings at the Australian and New Zealand Forensic Science Society symposium in Perth in September.
