ID the shoe, finger the culprit?
A new online crime-fighting tool was launched in Britain Thursday that may have villains quaking in their boots.
Forensic scientists unveiled the Footwear Intelligence Technology, a database of thousands of shoes, footprints, and other footwear patterns designed to help police quickly identify marks left at crime scenes and link them to other crimes and suspects.
In an era of high-tech forensics and DNA profiling, the notion of detectives studying a grubby imprint and then checking to see if the shoe fits may seem farfetched.
But forensic experts point out that the typical crime scene is more likely to produce shoe marks than fingerprints. Indeed, footprints are the second most common type of evidence found at crime scenes, turning up in around 2 in 5 cases. Only blood and DNA are found more often.
"This is about using the latest software and expertise to provide intelligence to police quickly and accurately," says Jon Goodyear, national footwear intelligence manager for the Forensic Science Service. "This will help police identify and apprehend offenders, and ultimately solve crimes, more quickly."
The online system, believed to be the first of its kind in the world, will be updated daily and contains thousands of footwear patterns, including sole markings, brand logos, and upper-shoe images.
The database will help police quickly compare footprints left at crime scenes with impressions taken from arrestees: New legislation means that police are now allowed to collect footprints from suspects in the same way as fingerprints and DNA.
Marks will be collected, studied in a laboratory, and entered into the database. Most are not the large, muddy boot marks common to TV detective shows, but are less apparent impressions that may have to be enhanced by UV light.
Investigators will also be able to use the marks and impressions left to prove that certain people own certain shoes – a technique known as "Cinderella analysis," which shows who the regular wearer of shoe is by studying the angle of footfall and weight distribution.
"It's not so much evidence, but it does provide good intelligence," says Professor Nigel Allinson, an expert in data engineering who has worked with police on a number of automated databases, including shoe models, fingerprints, and face-recognition applications.
"There's more of a chance to pick up footwear impressions that fingerprints in burglary cases," he adds. "The current trend for wood laminate flooring rather than carpets helps enormously and criminals tend to wear sneakers and they have sole patterns."
He adds that to get strong courtroom evidence, police will need to prove a mark was made by an actual shoe. "You look for something different, a molding perhaps, or a defect or crack." This is sometimes possible, he says, because criminals don't always think to throw away shoes that might incriminate them. "They dispose of the T-shirts, the jeans, but they don't always want to get rid of expensive sneakers."
Foot marks have proven vital in a number of recent crimes in Britain. A murder three years ago was finally wrapped up in December after police checked hundreds of individual foot imprints against marks that led away from the victim, out of her kitchen window, and down a street. In another case, 25 different footwear marks were retrieved from a number of burglary scenes, enabling police to link a number of suspects to the crimes.
But footwear may not always lead police to the perpetrator. Last year, it emerged that Unabomber Theodore Kaczynski used shoes with smaller soles attached to the bottom to make it look like a person with smaller footprints were behind the bombs.