Forensic tool linking victims to sex offenders could be key to solving cold cases where DNA is unavailable

A new forensic tool linking victims to serial sex offenders could be the key to solving cold cases when DNA is unavailable. In a world first, researchers at Murdoch University have developed Face Similarity Linkage, a new forensic intelligence tool connecting multiple victims to a single offender by identifying facial similarities. Some serial offenders — including American serial killer Glen Rogers, dubbed the Red Head Killer — are thought to be drawn to specific physical characteristics. Those who have been abused as a child are believed to seek victims with similar facial attributes to their abuser As part of the study, researchers analysed nine photographs of three random faces, identifying more than 20 facial landmarks, including the corners of the eyes and edges of the lips. The distance between each facial feature was then measured and converted into ratios, which were compared between each individual. Murdoch University School of Medical, Molecular and Forensic Sciences chair Associate Professor Brendan Chapman said FSL could be a “major win” to progress sexually motivated cold cases. “In cases where other opportunities have dried up, this may provide an additional tool for investigators to narrow down a pool of suspects in order to focus their investigation,” he told The West Australian. “If we take two people’s faces, we can look at the way that various features are distributed across the face and compare them to each other. “Some faces are more similar to one another, others are less, so we can statistically evaluate that to score their closeness, for example, how close or far ones eyes are.” Professor Chapman said FSL had the potential to be automated with artificial intelligence, allowing more victims to be screened faster. “An automated system could screen large numbers of victims quickly and reliably, giving investigators valuable leads where evidence is scarce,” he said. “While this technique can never replace DNA evidence, it can flag potential links between victims in cases where DNA doesn’t exist or has degraded. It gives investigators a new starting point.” He said researchers would continue to refine FSL by applying it to cases which had already been solved. “There’s still work to be done before it’s a case-ready tool but no intelligence is ever 100 per cent accurate, like an eyewitness report,” he said. “While this research is unlikely to be used for every case, it’s the toughest ones that it might help. “It’s easy to focus on the 99 per cent, but for anyone with family or loved ones that are the one per cent of cases, this sort of work is important.”