Few terrorist attacks have had such contrary explanations as the 1988 bombing of Pan Am Flight 103 over Lockerbie.
Sunday evening at 9pm the BBC2's Conspiracy Files enters the fray, examining some of the claims and counter claims.
One interesting question is whether the programme will feature either of Britain's two best known 9/11 'truthers' (and former MI5 officers) David Shayler and Annie Machon.
Shayler worked on the Lockerbie case (indeed MI5 are praised for their liaison work with the FBI over Lockerbie at pages 110-111 of the 9/11 Commission Report) whilst both he and Machon have since been indefatigable in defending the Anglo-American government position - that the Libyans did it, and any suggestion to the contrary is plain wrong.
So - will we hear Annie or David whistling the same old tune on Sunday?