by Mark McGregor
BBC News, Manchester
From the outside, there was nothing to suggest Michael Hamer was capable of a brutal killing.
Hamer was sentenced to life
Academically, the 14-year-old was at the lower end of average, he was something of a loner and mostly associated with younger pupils.
Hamer had endured being picked on by his peers, bullied for his dinner money and sometimes attacked.
And it was this victimisation he used at first to justify his frenzied attack on Joe Geeling, claiming he "just flipped".
"He said in interview that anyone could have been his victim, but my view is that he's selected Joe," said Det Supt Martin Bottomley.
"He has singled him out because of his illness, because he was young, because he was small and weak and not as heavy as him."
Rejected by boys his own age, Hamer retreated into his own world, developing a fascination with younger pupils.
He would go home after school, and, sitting in his bedroom in the evening, he developed a way of controlling others by retreating into a fantasy world.
Mr Bottomley, who led the investigation into Joe Geeling's death, said Hamer often spent hours playing computer games.
"There is nothing sinister in that," he concedes, "But we also know he tended to role play at being a teacher whilst he was at home.
"Again, nothing sinister in that, but just perhaps something a bit too immature for a boy of his age."
Hamer spent his time drawing up school timetables featuring the real names of younger pupils at St Gabriel's High School in Bury, Greater Manchester.
Michael Hamer's plot ended with Joe's body dumped in a gulley
Psychology professor Cary Cooper, of Lancaster University, said any child exhibiting this kind of behaviour would have a very clear reason.
"It's because they want to be in a role which has some kind of control," he said, "Which would indicate to me that they feel they don't have control in their ordinary school life.
"But why that fantasy world should then turn to extreme violence is another matter," he added.
Mr Bottomley said :"In his mind, three weeks before the event, he has selected Joe as a victim. He's selected him as someone he wants to harm."
The most disturbing aspect of Hamer's behaviour, Mr Bottomley said, was his detached demeanour and his composed planning and execution of his plan to lure Joe to his death.
Joe was last seen making the short walk home from school
"He acted in a perfectly rational way. He placed Joe into a wheelie bin within minutes of killing him. He walked him through the streets of Bury. He took mobile phone calls from his mum while he was wheeling him through the streets of Bury, acting as if nothing was out of the ordinary.
"He then went back to the house, he then cleaned up. He then did his homework. He then went to school the next day as normal and when questioned about the acts and the sightings during the course of the morning just shrugged and lied his way through them."
Traumatised by the incident, Hamer's mother has moved away from the house in which Joe was murdered and now faces the prospect of her son spending a long time in custody.
Mr Bottomley added: "How does she cope? She's lost a son as well."