The allegation was made by Donald Findlay, the defence QC, after a former Strathclyde Police detective appeared to change his story during the trial of John Docherty, who is accused of murdering Elaine Doyle in 1986.
John Wilson, 66, who left the police in 1997 after 30 years' service, was one of the first officers on the scene after the naked body of the 16-year-old was found in a lane near her home in Greenock.
The High Court in Edinburgh has already heard of controversy over whether a police blanket was draped over the teenager to protect her from being seen by neighbours.
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.
"If I had seen a blanket on the deceased I would have taken it as a production," he told advocate depute John Scullion, prosecuting.
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 the blanket should have lodged but it never seemed to be."
Mr Findlay is defending Mr Docherty, 49, now of Hunter's Quay, Holiday Village, Dunoon, who denies murder.
Mr Findlay asked Mr Wilson to look at the accused and challenged the ex-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."
Mr Wilson replied: "I don't know."
Mr Findlay promised to keep questioning him "until hell freezes over" to get the truth.
The lawyer said it was not enough for Mr Wilson to continue to claim he could not remember details of the July 2012 interview. Mr Findlay asked: "They put words in your mouth?" and Mr Wilson agreed. "It would appear they wrote that, yes," he said.
Mr Findlay continued: "So your position is that Strathclyde Police in July 2012 fabricated evidence and put words into your mouth?" Mr Wilson said: "Yes."
Mr Docherty claims that at the time he is alleged to have stripped and strangled Miss Doyle he was at home with his parents, who are no longer alive.
Docherty has also lodged a so-called special defence of incrimination, claiming the culprit might be among a list of 41 names taken from files of the police investigation into the murder.
The charge alleges that on June 2, 1986 in a lane near Miss Doyle's home in Ardgowan Street, he seized her by the hair, struck her on the head and either removed or compelled her to remove her clothing.
The charge goes on to allege Mr Docherty forced her to the ground, pushed her face into the ground, sat or knelt on the teenager, then placed a ligature round her neck and strangled her.
Mr Docherty also denies stealing a handbag from Ardgowan Street on the same date.
He further denies a charge of attacking another woman, Linda Hargie, on various occasions between 1990 and 1995 at an address in Anne Street, Greenock by seizing her and pushing her and punching her on the head.
The trial continues.