A detective who arrested and interviewed one of James Bulger’s killers has revealed the moment he knew he was lying and realised that "these boys had done it".
Phil Roberts said every time he asked Robert Thompson a difficult question, he would shuffle his legs under the chair, and he knew he wasn’t telling the truth.
The sergeant has said that although in his experience he has "seen everything" he doesn’t think "there could be anything worse than that particular murder."
Phil Roberts was a detective sergeant with Merseyside Police when two-year-old James Bulger was abducted in Merseyside on February 12, 1993.
Mr Roberts arrested and interviewed Thompson after James’s body was found two days after he was taken.
Two-year-old James Bulger was led away from his mother, Denise, by two young boys in a shopping centre near Liverpool.
He was later found after being tortured and killed by Jon Venables and Robert Thompson.
The 10-year-old boys had beaten James and left his body on a railway line.
Speaking to the BBC, Mr Roberts said: "On the Sunday afternoon myself and other officers were sat in the CID office looking at the CCTV and trying to establish where the two boys were that led James Bulger out of the Strand.
"I heard a terrible sort of scream from the gut, and it was coming from Denise, from where the family of James Bulger were. And then I realised the body had been found. There’s no doubt – it wasn’t an accident."
He told the BBC he was 43 years old with 24 years of police service when he arrested the young boy.
He said: "I had seen everything. Nothing had really surprised me. This did – and I don’t think there could be anything worse than that particular murder."
Speaking on the ITV programme James Bulger: A Mother’s Story he described Thompson and Venables trying to blame each other for the murder.
Mr Roberts, who said he had been on a course to deal with children, said: "He thought, by what he said he wasn’t going to be proved that he killed James.
"He came down to earth when we said ‘we’re going to charge you with his murder’.
"But then, when we brought in some toys and books he was blasé to what he had done. Totally blasé."
The pair were both convicted of killing James and were released in 2001 after eight years of detention. They were both given secret identities and addresses.
Mr Roberts, from Llanrhaeadr-ym-Mochnant, near Welshpool, said that as he started to interview Thompson he realised he was not telling the truth.
"We had one witness give a statement to state that one of two boys had blue paint on their shoes…. Blue paint had been found on James Bulger," he said.
"My initial thoughts were ‘A 10-year-old to commit such an horrendous act, the injuries that were caused on James Bulger? Right, I will negate this boy from my enquiries’.
"It was only as you start interviewing you establish that he was lying, and why was he lying?
"He gave it away by shuffling his legs under the chair. Every time you gave him a hard question, he would shuffle his feet on the chair.
"He eventually started admitting that he and Venables had taken James from the Strand but left him."
He added: "I thought ‘We’ve got them, these boys have done it’."
Mr Roberts said the crime played on his mind, especially when he got home and was with his children.
"You just sit so quiet. You’re motionless really," he said. "My daughters realised that. I think they knew when to keep quiet."
- The interview tapes in the video have been taken from the ITV documentary – James Bulger: A Mother’s Story, which is available to watch on the ITV Hub.