It was reported that the trigger found by the US teams several weeks/months after the explosion was of the type favoured in Libyan- not Palestinian-made bombs, thereby ruling out the Abu Nidal/Iranian scenario.
But apparently an honest Swiss arms factory worker, plagued by his conscience, a couple of years back finally lodged a sworn statement that just after the accident he had been approached by the CIA who requested a sample timer (of the Libyan type) to help with their investigations, which he duly supplied. It was this very timer, recognisable to him in the court photos, that was then 'discovered' on the accident scene.
Had the Scottish judiciary re-opened the case, this testimony was the 'smoking gun' that would have reversed the conviction - and into the bargain humiliated the Scottish justice system for their ineptitude and possible complicity in the original trial. Hence the essential pre-condition for letting fall-guy Megrahi out was that he dropped his appeal - an act misconstrued by the media as further proof of his 'guilt'. Allegedly.