James Bulger murder: Arrest detective cannot forgive

James Bulger's body was found two days after he was snatched

The Welsh detective who arrested one of the 10-year-old boys who killed toddler James Bulger 20 years ago says he will never forgive them.

Phil Roberts, of Powys, said at first he did not believe Robert Thompson could have murdered the two-year-old on Merseyside on 12 February, 1993.

But he realised he was guilty - along with another 10-year-old, Jon Venables - when he began interviewing him.

The crime shocked Britain, and he said Thompson was the vicious ringleader.

He spoke as James' mother, Denise Fergus, described how she still "wants justice" 20 years after she let go of her small son's hand in a Bootle shopping centre and never saw him again.

Thompson and Venables abducted and murdered James, beating him with bricks and iron bars and leaving his body on a railway line. James' body was found two days after he went missing.

Both were convicted of killing him. Thompson was released in 2001 after eight years in detention, and given a new secret identity and address.

Venables was also released on licence in 2001 after serving his sentence but was jailed for two years in July 2010 after admitting downloading and distributing indecent images of children. He has been refused parole.

Mrs Fergus has campaigned to have both kept in prison, and said: "I did warn [the authorities] that one of them or both of them would go on to reoffend, and I was proven right with Venables."

Mr Roberts was a detective sergeant with Merseyside Police in 1993 when he arrested Thompson.

Now retired and living in Llanrhaeadr-ym-Mochnant, near Welshpool, he also said he was not shocked to discover that Venables had been taken back into custody.

Mr Roberts met Mrs Fergus recently, and said that like him, she will never forgive the killers.

The two boys were caught on CCTV taking James out of the shopping centre, and he recalled how Thompson was taken into custody:

"I went after Robert Thompson, arrested him and took him to Walton Lane police station to interview him," he told BBC Radio Cymru.

"When I first saw him, a 10-year-old, I thought no way he could be responsible for murder.

"He was shrewd. He was lying. After four interviews he said that he saw Jamie Bulger but hadn't taken him," he told the Post Cyntaf programme.

CCTV showed James Bulger being led away from a Bootle shopping centre on 12 February, 1993

He said it was not hard to interview him, as he had experience of questioning youngsters. But Thompson was "a vicious person," he added.

Mr Roberts saw Venables only when he appeared in court. He described him as "hyperactive" but believed Thompson was the "ringleader" behind the murder.

The crime led to a national debate about young offenders, and Det Ch Supt Albert Kirby, who led the murder inquiry, said it highlighted that "children were capable of doing some very evil and violent things".

Police discovered that they had set out to murder, after trying to take another boy a couple of hours earlier and planning to push him under a bus.

But Mr Kirby said: "The question is always why? Even now I don't know why they did it".