Three times within three months, Mr Grieveson strangled victims in his Sunderland neighbourhood. Each body bore the same signature: a ligature knotted carefully with a half-hitch to the left of the back of the victim's neck and which left no mark, John Milford QC, for the prosecution, told the jury.
Mr Grieveson, 24, denies murdering Thomas Kelly, 18, and 15-year-olds David Hanson and David Grieff between November 1993 and February 1994.
The killings had "numerous and striking" similarities which led to the conclusion that only one murderer could have been responsible, Mr Milford said.
But local pathologists had been unable to prove homicide from post-mortem examinations. Only when they consulted two experts, six months after discovery of the third body, did compelling evidence emerge that all three boys had been killed.
Thomas Kelly had been strangled with his own scarf in an allotment hut; David Hanson with a scrap of material from an unoccupied basement; and David Grieff with his own belt in an allotment shed close to the scene of the Kelly murder.
Mr Milford told the jury of six men and six women that all the killings took place in the evening, "after dark, but not late".
At the scene of the Hanson killing, Mr Grieveson's fingerprint was found on a basement window. On boarding torn down to force entry, police found a footprint which matched the sole of Mr Grieveson's training shoe.
A DNA profile taken from semen found in David Grieff's mouth and stomach matched Mr Grieveson's DNA. Profiles match once in every 200,000 people, Mr Milford said.
The court was told that after a chance meeting, Mr Grieveson had lured David Grieff from the company of his friends with an unfulfilled promise of cannabis. The boy was not homosexual. "He forced David Grieff to fellate him, and then he murdered him," Mr Milford said.
Mr Milford said it was unnecessary for the Crown to establish a motive for the alleged murders. But Mr Grieveson was a homosexual "unable or unwilling" to come to terms with his sexuality. He killed to prevent the boys revealing the homosexuality he had disclosed to them, and he killed "because he enjoyed killing them and firing their bodies".
Mr Grieveson met Thomas Kelly in Sunderland town centre on 26 November 1993. Mr Kelly was afraid of Mr Grieveson because he had joined an identity parade on which Mr Grieveson was the suspect.
Mr Kelly feared Mr Grieveson mistakenly believed he had been betrayed to the police by Mr Kelly, the jury was told.
When Mr Kelly's body was discovered later that night it had been burned so badly that a police doctor could not establish his sex.
David Hanson and David Grieff were friends and members of a group who had experimented with drugs, Mr Milford said. Both attended Monkwearmouth Secondary School, where Mr Kelly had also been educated.
David Hanson's body was found in an unoccupied seafront house which Mr Grieveson later admitted burgling. He claimed that his theft from the house explained the presence of his fingerprint and footprint.
Mr Milford said the prosecution would show the premises were secure when Mr Grieveson said he broke in. And witnesses would testify they saw Mr Grieveson with David Grieff on the evening of his death.
Mr Milford said Mr Grieveson admitted his homosexuality later to a cellmate at Durham prison. He admitted having sex with "a lad" whom he had killed and then burned because he was on drugs.
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