A schoolboy was tortured and strangled before his body was dismembered and parts dumped in a canal, a court heard yesterday.
John Milmo QC, for the prosecution, warned a jury at Nottingham Crown Court that the evidence would be "unpleasant and distressing".
Matthew Welsh, 19, Daniel Biggs, who turned 19 yesterday, and Sarah Morris, 17, all deny murdering Adam Morrell, 14, of Loughborough, Leicestershire, but have pleaded guilty to conspiracy to pervert the course of justice.
A fourth person, Nathan Barnett, 27, has pleaded guilty to manslaughter on the grounds of diminished responsibility and to conspiracy.
Mr Milmo said Adam suffered more than 280 injuries during the torture at a house where he was staying in Loughborough. His said the death was an act of "great cruelty".
Adam, Mr Milmo said, was beaten and punched by each member of the gang and doused in boiling water before being strangled.
His body was hacked with a saw in the bathroom, wrapped in black plastic bags and dumped in and around a canal. Members of the gang told police how they had played loud music to drown out the noise as his body was sawn into pieces.
Mr Milmo said: "Adam had been subjected to a prolonged and, we say, vicious assault over a period of time and over a period lasting a day or more. There was sufficient head injury caused, almost certainly by repeated blows to the head and face, to have caused death but marks found on the neck also suggested strangulation with some form of ligature although [the pathologist] could not rule out strangulation manually."
The court heard Adam was a "handful" at home and at school and had been expelled several times.
He called his father in the days before his death to say that he was staying with friends for the night and they never heard from him again.
He was last seen on 15 November last year at a fair in Loughborough with friends. Parts of his remains were discovered two days later by a group of people walking along the canal.
Over the next few days, his torso and legs were found in separate locations around Loughborough and a bag containing his clothes was recovered by police from an electricity substation.
The boy's head was wrapped in a black plastic bag and was found by underwater search teams in the canal. Only one limb was never recovered, Mr Milmo said.
Each defendant gave a different account to police of the extent of their involvement in the torture, said Mr Milmo, but one said it had lasted for around three to four hours.
Mr Welsh and Miss Morris, who was his girlfriend at the time, admitted striking the boy but said they had not been involved in killing him. Mr Biggs denied carrying out an assault.
Miss Morris told police she saw Adam the next day and he was "looking like an alien - he was unrecognisable". She said that Barnett made the decision to kill Adam and that she put the music up to drown out the noise of Adam choking.
Mr Milmo said Barnett had first told police that Adam had been killed in a churchyard before being taken to the canal bridge where his body was cut up, an account initially supported by the others.
The trial is expected to last three weeks.Reuse content