Detectives revealed that the three youths, Thomas Kelly, 18, who was found dead last November, and David Hanson and David Grieff, both 15, who were murdered in February, are believed to have been victims of the same killer. All the incidents took place in Sunderland, where the boys all attended Monkwearmouth Comprehensive School.
The bodies of Thomas Kelly and David Grieff were found in burnt-out huts yards apart in allotments at Monkwearmouth, David Hanson was found in a fire-damaged derelict house half a mile away in Roker Terrace. In each case solvents were found near the body and it was suggested that experimentation with drugs was to blame.
At that time police dismissed speculation that the deaths were suspicious or might be the work of a serial killer. The youths' parents have always denied that their sons were drug-takers or glue- sniffers and argued that they may have been murdered. They welcomed the police announcement yesterday which they said cleared their sons' reputations.
The police said that the teenagers were discovered to have been murdered only after lengthy scientific examination. The original cause of death had been given as asphyxiation.
The investigation was hampered by the extensive fire damage to the bodies and at the scene of the crime, said Detective Chief Superintendent Barry Stewart, head of Northumbria CID. He denied the police were at fault. He said: 'It's only through our persistence that we have been able to reach the position we are now in.'
In each case empty lighter fuel canisters were found near the body. One theory is that the fires were started by the murderer to destroy evidence.
A sexual motive for the attacks is being considered, but the police have refused to disclose whether the teenagers were sexually assaulted.
The police are sure the murders were carried out by the same person or people because of the many similarities between the killings.
They are also examining the possibility of a link with the unsolved murder of another Sunderland schoolboy, Simon Martin, three years ago. He was found battered to death in a derelict building not far from where David Hanson's body was found.
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