One small step for man, one giant leap for forensic science?
04 August 2008
Forensic experts at the Scottish Police Services Authority (SPSA) are leading the way in the research of new ground breaking forensic techniques within the field of podiatry.
Following discussions with a local podiatrist, Dumfries based Scene Examiner Andrew Bain began to investigate the potential of applying podiatry techniques and technology to his forensic work.
Podiatry looks at how the foot functions, how the limbs and the rest of the body affect the foot and how we actually walk. Like a fingerprint, every foot leaves its own unique pattern on the surface it comes into contact with. Andrew recognised the importance of this and the value it could bring to expanding forensic investigation techniques.
Footwear marks are already an established form of evidence for scientists and scene examiners but whereas this type of examination looks at the pattern detail on the sole of a shoe and any distinguishing features or unique damage, the new research looks to compare how a person walks, how their foot falls on the ground and the different pressures associated with this. It's known as the ‘Gait Cycle' and is unique to every individual.
Andrew said:
"I have always had an interest in footwear evidence and felt that its importance in an investigation was not always recognised. My thinking was that if the way a person walks and leaves a footprint is unique to them, then we should be able to record it for crime scene purposes and it should have evidential value.
"Allowing for certain illnesses, how you walk should generally remain with you for life. If we can record an image of how a suspect's foot falls on a particular surface, and we know that this footprint remains consistent, we could then compare it to a mark left by a suspect at a crime scene.
"The patterns of existing footwear evidence, which can have a shorter life span due to additional damage and markings caused by further wear of the shoe by an individual, would also be strengthened by the new developments."
Teaming up with leading podiatrists at Glasgow Caledonian University and Sheffield Primary Care Trust, Andrew's research is in the early stages but has the potential to have an impact worldwide.
Gordon Burrow, Senior Lecturer in Podiatry, Glasgow Caledonian University said:
"There are certain characteristics on a person's foot that will remain the same. For example if you have bunions then they will always be present and will give you a certain wear mark. If you've got a very rigid first toe, then that will also give you a certain wear mark, and it doesn't really matter where you are or what you do, you will still have that particular wear mark.
"Used on its own this will not necessarily convict a criminal but used alongside other evidence it will present a more robust case to the court."
The team's current studies have led them to look at the pressure areas on a foot and compare this with a known foot mark from a volunteer. From this they have been able to identify if the person had worn particular shoes in question and whether they left certain wear marks either on the outsole or the inside of the shoe drawing a comparison between the two.
For example, this means that should a suspect agree that their shoes did leave the footprints recovered from a crime scene but argues that someone else was wearing them, the new developments will help to prove or disprove this theory by matching the indentation marks on the shoe to the areas of greatest pressure caused when the person walks.
Or as Andrew Bain explains:
"In a scenario like this, if a suspect has really ‘walked the walk' then the addition of this technique will make it much more difficult for him to ‘talk the talk' to get out of it."
The forensic experts hope to take this further by looking at particular correlations between a person's height, their weight, BMI (body mass index), foot length and width and the type of foot they have to understand the impact that this has on their footprints they leave behind.
Forensic podiatry has only been recognised as a new discipline in the last 18 months and whilst Andrew Bain's research is expected to take a number of years to reach fruition, SPSA Forensic Services is determined to be in the vanguard of this exciting new development.
Director of SPSA Forensic Services Tom Nelson said:
"It is just over 16 months since we brought together forensic services into a national crime scene to court service. I am determined that we balance the consolidation of the core forensic support we provide to the police and the Crown, with new innovations and techniques. This is just one such innovation we are pursuing as we strive to ensure that forensics makes an even greater contribution to convicting the guilty and protecting the public."