The allegation came from defence QC Donald Findlay after a former Strathclyde Police detective appeared to change his story.
John Wilson, 66, who left the force in 1997 after 30 years police service, was one of the first officers on the scene after the naked body of teenager Elaine Doyle was found in a lane near her Greenock home.
The High Court in Edinburgh has already heard of controversy over whether a police blanket was draped over the 16-year-old girl to protect her from nosey neighbours.
Yesterday Mr Wilson told the trial he did not see a blanket over the girl. The jury was also read a statement the retired detective gave in July 2012 in which he said: "I have been asked about a police blanket being placed over Elaine's remains. I do remember seeing a blanket on the deceased."
Mr Wilson said at the start of his career he was told "keep your hands in your pockets" at a crime scene and not to touch anything. He also said that during the first months of the murder investigation he was responsible for the safe-keeping of productions in the case.
He told advocate depute John Scullion, prosecuting: "If I had seen a blanket on the deceased I would have taken it as a production."
But he said he did not remember being questioned about that when officers visited him at his home.
His statement read: "I definitely saw the body covered with a prisoner's blanket but I don't remember who put it there."
Mr Wilson told the prosecutor: "I don't think I would have said that to be honest."
He also doubted that he had said: "I remember thinking at the time that the blanket should have been lodged but it never seemed to be."
John Docherty, 49, now of Hunter's Quay, Holiday Village, Dunoon, denies murder.
His QC, Mr Findlay, asked Mr Wilson to look at the accused and challenged the former-detective: "He has been accused of the murder of a young girl back in 1986 - well over 25 years ago and from your evidence alone, Mr Wilson. It is, I suggest, glaringly obvious that the Strathclyde police, past and present have fabricated evidence in this case."
Me Wilson replied: "I don't know."
The trial continues.