Fresh doubts have emerged over the conviction of the Lockerbie bomber, BBC Scotland has learned.
Megrahi was convicted of the Lockerbie bombing in 2001
The evidence of a major prosecution witness who testified during the trial of Abdelbaset Ali Mohmed al-Megrahi has been called into question.
Three men who forensic scientist Allen Feraday gave evidence against have since had their convictions quashed.
BBC Scotland understands papers on one case have gone to the commission reviewing Megrahi's conviction.
Mr Feraday is now retired after 42 years' experience in explosives.
He told the Lockerbie trial he was in no doubt that a circuit board fragment found after the disaster was part of the detonator.
The trial judges accepted his conclusion.
However, in three separate cases men against whom Mr Feraday gave evidence have now had their convictions overturned.
The bombing claimed the lives of 270 people
After the first case, which took place seven years before the Lockerbie trial, the Lord Chief Justice said Mr Feraday should not be allowed to present himself as an expert in the field of electronics.
The latest case to be quashed happened just last month.
Papers relating to the most recent case have now been sent to the Scottish Criminal Cases Review Commission, which is looking at the Lockerbie bomber's conviction.
The commission will consider whether the Lockerbie trial judges should have given so much weight to Mr Feraday's evidence.
Gerry Brown, of the Law Society of Scotland, said expert witnesses were "essential" in cases like the Lockerbie trial.
"It is like a string of beads," he told BBC Radio Scotland.
"You have to have the beads held together by string, and if the string is weak at one point the beads fall to the ground.
"That is possibly the situation here, and that is probably what is being investigated now by the commission."
Solicitor Eddie McKechnie, who represents Megrahi, said the information raised "serious issues" about the conviction.
"It is a factor that I take very seriously into account on behalf of Mr Megrahi," he said.
"One would have thought that when a professional and a government forensic expert is impugned in a number of cases... then serious issues arise."
Dr Jim Swire, whose daughter Flora died in the bombing, said: "I'm personally not satisfied of Mr Megrahi's guilt.
"I emerged (from the trial) riddled with doubts. This will of course augment them.
"If one finds that three cases have been overturned, it rather undermines one's confidence."
However, American lawyer Jody Flowers - who represents one woman whose husband died in the bombing - said she thought the latest claims were "much ado about nothing".
"I don't think it has much impact at all. I think it is a bit of a belated and half-hearted attempt," she said.
"Any serious challenge to Mr Feraday's credibility or the specifics of his testimony would have been raised at the trial or the appeal, and they were not.
"The court accepted his testimony as reliable."
She said he was a "highly qualified individual" whose evidence had been corroborated by others.
Ms Flowers said one of the cases in question had been five years before the Lockerbie explosion - and 16 years before he gave evidence in the trial.
Mr Feraday has been invited to comment but has so far declined.