Jon Venables wept every day of his three-week murder trial, a quivering, vulnerable contrast to the boy he sat beside. When the verdict was passed he broke down, and said as he was led away: "The little boy, will you tell his mum I'm sorry."
Emotionally immature, with two siblings with learning disabilities, he appeared younger than Robert Thompson, and was certainly the more impressionable of the two. It had been his idea, however, to approach James Bulger in the Strand shopping centre.
His interviews with police and psychiatrists at the time of his arrest revealed a frightened and confused boy, unable to comprehend the full horror of what he had done but well aware of the consequences. He said he wanted "a world filled with chocolate", and as the police questioned him, his mother at his side, he cried: "Mum, I never," he said. "I never touched him by the hand, I never even touched a baby. I never took a baby. I want to go home. . . you're going to put me in jail."
One of the officers described the moment he confessed to his parents as the police looked on. "He ended up sort of curled up on Sue's lap and he was crying and crying and they said over and over that they loved him and would always love him and then, really very quickly, he said: `I did kill him."'
At the time of the murder his father Neil lived away from the family and Jon would visit him to watch videos. One of these, Child's Play 3, was mentioned in court as a trigger for the crime, a theory derided as nonsense by one investigating officer.
Venables is said to be overweight, a result of binge eating brought on by boredom. He has not made the educational strides that Thompson has, but he has made progress in coming to terms with his crime.
Psychological reports published in 1995 said he had moved through a succession of mental states: denial, grief, confession, and remorse "that would remain forever".
Thompson was known as Child A throughout the three-week murder trial at Preston Crown Court, and many of those close to the case believe him to have been the prime mover in the killing.
During the trial he became known as "the one that did not cry", and he returned the questioning stares of the press bench unblinkingly. For years he failed to accept any responsibility for Bulger's death.
Detectives who interviewed him following his arrest described him as canny, intelligent and frightening. They were unnerved by his failure to react like a confused child, and some came to hate him, regarding him with a contempt usually reserved for sex criminals and adult child killers.
The police were also shocked at his size. He was so short that the officer who told him he wanted to "ask him a few questions" had to get on his knees. Venables insisted in police interviews that Thompson had bullied him, and that it was Thompson's idea to kill Bulger.
Thompson's brutal father walked out when he was six and has not made contact with him since his arrest in 1993. His mother Anne, violently alcoholic at the time of her son's arrest, sobered up and moved to within walking distance of the secure unit in which he has been housed since he was sentenced. Along with her three younger sons, and her eldest who lives at home, she visited Robert every day.
Diagnosed as having learning disabilities when he was imprisoned, he achieved five GCSEs in 1999 and moved on to A-levels in design and technology. He has shown aptitude for art, particularly textiles.
In 1999 he was reported to have at last acknowledged responsibility for what he did and is said to bear an extreme sense of guilt.