AI software helped convict pedophiles, police say – BBC News

Advanced AI software was instrumental in proving that a pedophile groomed and sexually abused girls, police reveal in a new TV programme.

The conviction of Luke Cassidy, 29, of Coventry, was documented by BBC Two’s Forensics: The Real CSI.

Investigators said they struggled at first to find enough evidence to show that Cassidy controlled and groomed the girls.

But through his phone they kept finding deleted messages and photos which led to his conviction in January.

Warning: This article contains information that some people may find distressing.

Cassidy was arrested when a 12-year-old girl reportedly groomed her on the social media platform Snapchat and then raped her.

But while he admitted to detectives that he had sex with her, he claimed she had told him she was 16. Also, his victim’s account of solicitation needed corroboration for the prosecution.

First, Cassidy’s Nissan Juke was impounded by police as forensic coordinator Jo Ward said the victim told them she had been inside the vehicle.

But the evidence only showed that Cassidy had sex with it – there was no DNA linking his victim to the car.

Digital forensics officer Dan Coley then examined the phones of the defendant and the victim, but could only prove that they knew each other and had spoken to each other.

“There is nothing potentially to support the victim’s account of what happened,” he said of an initial phase of the investigation that ran the risk, he added, of being “the end of that investigation.”

But then came a breakthrough, along with the means to unlock Cassidy’s account.

Investigators explained that a 13-year-old girl had come forward to inform them that she had been sexually propositioned by a man online.

When it became clear that Cassidy was behind that content, the detectives were finally able to build a case against him that could bring the first victim within their range.

Artificial intelligence (AI) allows computers to perform complex tasks. In this case, specialized software was trained on the words used in Cassidy’s messages to the second victim and then applied to search for similar language anywhere on Cassidy’s phone.

Indecent images of children were discovered in addition to messages showing that he was treating children and was indeed a predator, Coley said.

Cassidy was then charged. In court, she pleaded guilty to one count of rape and one count of possession with intent to supply Class B drugs, but denied one count of online soliciting and five other counts of rape.

However, he was convicted of all charges at Warwick Crown Court in December and jailed for 19 years, with another five years off leave. He was also placed on the sex offenders registry indefinitely.

“This achievement is important to me,” Coley said. “Not just as a parent, but also in the hope that ultimately we’re here to try and help save children.”

Det Con Corinne Hatton, of West Midlands Police, said Cassidy had targeted the most vulnerable in society and had “caught himself innocent”.

Police said 14 more victims had been discovered by June and officers were working to identify and back them up.

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