Revolutionary new forensic techniques that could help police track down criminals have been developed by Dundee scientists.
The Abertay University team’s pioneering work can now recover invisible prints left on fabric by the sole of a person’s shoe for the first time.
Last year researchers at the university made the headlines when they recovered invisible fingerprints from fabrics.
Now, by adapting and modifying existing print visualisation techniques, Dr Kevin Farrugia has developed the world’s first detailed images of latent footwear marks left on fabrics.
The information these provide will enable police to identify perpetrators of serious crimes in cases where, for example, no fingerprints or DNA can be recovered from the scene.
Dr Farrugia said: ”Footwear marks can be made in many contaminants, for instance blood, mud, urine and dust.
”They can be left on all sorts of different fabrics, like cotton or denim, as well as on patterned and dark material, which makes them more difficult to see.
”They might be left on the body of a murder victim if the perpetrator kicked or stamped on them during an attack, or they might be made by traces of blood that the perpetrator picked up on their shoes and left on the carpet, or other types of flooring, before leaving the victim’s house.
”When someone steps in wet blood, though, the first few prints they leave will be a wet smudge, so no fine detail from the footwear sole can be recovered.
”However, as the marks fade and becomes less visible, the pattern on the sole of the shoe, by contrast, becomes much clearer and better defined.
”It’s these prints the ones that we can’t actually see that are the most useful at a crime scene, especially when it isn’t possible to recover other types of evidence, such as fingerprints and DNA, because they can tell you things like what size, and even what brand, of shoe the perpetrator was wearing when they committed the crime.”
Previous attempts to recover footwear marks from fabrics had generally obliterated, rather enhanced, the image, because the right mix of the right types of chemicals had never been formulated.
Dr Farrugia’s techniques bring the print to the fore without damaging it, and produce a clear and highly-detailed image.
They work on fresh prints, as well as older ones, and could be used to help solve cold cases as well as new ones.
He added: ”More importantly, because everyone walks differently, the sole of their shoes will have acquired what we call random and individual characteristics that are specific to that shoe and person, which means, when the police have got a suspect, they can get their shoes, and if the shoes match, it can lead to a conviction.”
Since joining Abertay, Dr Farrugia has written guidelines on techniques for each contaminant and material.