Scientists believe they can identify paedophiles based on characteristics of their hands, and potentially track their movements around the world.
Dame Professor Sue Black, of Lancaster University, has developed a forensic technique to identify suspected offenders based on pictures of their hands.
She has worked on the process since 2006 and hopes eventually to automate it. She began building a database to work out the probability of two hands having the same features while working at the University of Dundee.
She said: “If we’re able to automate, then we would be able to use these algorithms that we’ll develop, to sift through the millions of images that are held on databases by police forces around the world.”
“The chances of you being able to link them before have been close to zero, so we can maybe get to a point of being able to track where these perpetrators have been going around the world.”
Currently all analysis is performed by eye, Prof Black said.
She added: “It’s a spot-the-difference type comparison, that game you used to play as a child. I’ve got this image, I’ve got that image. What’s the same and what’s different?”
“We will look for patterns of skin pigment. We will look for vein patterns, superficial vein patterns. And we will look for the pattern of creases of skin over the knuckles.”
The technique will now feature in a BBC documentary, The Hands That Convicted A Paedophile.
The broadcaster said Prof Black’s analysis technique had already been used to secure the conviction of one paedophile.
Jeremy Oketch, now 38, was convicted in 2015 of raping a two-year-old girl and sentenced to 15 years in prison. He had filmed himself doing so, Greater Manchester Police (GMP) said, and the footage was described as “exceptionally disturbing”.
Scientists compared footage of Oketch’s hands with photographs taken in custody, and matched “every anatomical feature”, Prof Black said.
Pharmacist Oketch pleaded guilty, GMP said in a press release at the time.
Detective Chief Inspector Colin Larkin, who investigated the rape, told the BBC for the documentary: “It was brilliant. It had gone beyond my expectations. She had proven beyond all reasonable doubt that he was guilty.”