Set aside the forensics and the experts.
These things are the best guesses of the Best Guessers. In the first days after any seemingly unfathomable event it would be wise to treat such opinions as speculation and conjecture by people trying to give the media some good copy. A Fatal Accident Inquiry did put together a working hypothesis of why thousands of pieces of 747 jumbo-jet crash in and around Lockerbie. It started a manhunt. Despite all the credible warnings and some not-so-credible claims for responsibility there was no-one to put in the frame. That's discounting Khaleed Jafaar, a young Lebanese man with American citizenship.
Set aside the computer records for Frankfurt airport.
This actually happened. For the 21st December 1988 not one official from the police to the airlines thought that information on which passengers flew where, carrying whatever luggage, might be useful. One scrap was saved and this has become known as the "Erac Printout" With cross-referencing to the baggage-handlers' worksheets it can show a suspicious looking item being put aboard at Frankfurt. Weirdly, The Independent, of 17th January 1989, was reporting 'from political sources' that the investigation was working along these lines and this was before anyone really knew of the Erac Printout. The EP was handed to the MacPlods in August 1989.
Set aside the paid-off witnesses.
These things are only ever going to tell you what they think you want to hear. This is a sure sign of desperation in investigation into a crime in which the investigators seem to purposefully look away from their initial hunches and leads.
Madjid Giaka, a Libyan man on Malta with a cash-flow problem has convinced the CIA that he's a top-level employee of Libya's intelligence agency ( JSO ) The CIA put him on the payroll and are probably disappointed very quickly in how little to next to nothing Giaka can tell them. On the verge of being dropped from the payroll Giaka informs his 'handlers' that he saw Megrahi and Fhimah placing a suitcase on the carousel for flight KM180 at Luqa Airport, Malta on Dec 21st 1988. It is this evidence that makes Giaka the prosecution's star witness. Unfortunately Giaka reverses his crucial statement to say that they were taking a suitcase off the carousel. He and his testimony are ignored by the Zeist judges, but he has proved his dollar value to the prosecution by getting two Libyan's to court in the first place.
Toni Gauci is another paid witness. Not the sharpest pencil in the box by all accounts, he is cajoled over the course of something like 13 official interviews and half a dozen photo-spreads into confirming that Megrahi resembles the man who bought some clothes from him. Perhaps the all expenses paid holiday to Scotland would jog his memory? Nope. The likelihood of a cool £million? Not exactly. As an aide-memoir Gauci carries a magazine article showing Megrahi as the accused to the trial. This ups his identification prowess to "resembles him a lot." Sheesh. Mind you, Gauci was sharp enough to know when he'd picked the photo the MacPlods wanted him to choose in one of the photo-spreads. He becomes agitated and concerned that "they" will now be out to get him. The point to be made here is that the investigating officers should not have been present when the photo-spread was being viewed.
Set aside any evidence of zero competent security at London Heathrow. Break-ins and/or any testimony from baggage loaders telling the investigation that they did not place all the luggage into the container that held the suitcase bomb?
It's exactly what the investigation did. It seems to be forgotten that the first person to mention a Samsonite-style suitcase of approximately the right colour was a baggage loader at Heathrow. He volunteered this information at an interview before such details were in the public domain. He did give evidence at Zeist, which was waved away by theorising that this suitcase must have been moved to another part of the container, a more or less identical one taking it's place. After all it had been decided that the bomb went aboard at Frankfurt despite better evidence for Heathrow. As for the break-in in the early hours of 21st December 1988? That evidence was not even heard at the original trial. At the appeal the evidence was waved away as workers forcing a lock to take a shortcut.
To save me, and you, from many more rambling paragraphs I'll surmise what the Zeist judges bought:
Mr Megrahi, who resembled a man that bought clothes in Malta on a day that it can be proved he wasn't in Malta, was at Luqa Airport on the morning of 21st December 1988.
The clothes in question ended up in a suitcase with a bomb that was transferred from a Malta Airlines flight at Frankfurt Airport onto a Pan Am feeder flight ( PA103A ) bound for London Heathrow.
The suitcase went into the hold of Pan Am 103A, along with 20 other suitcases 'interline'
The suitcase with the Malta clothes, and the bomb, was then transferred from Pan Am 103A at London Heathrow into Pan Am 103 to New York.
( Crucial things to ignore here: Air Malta proved that no unaccompanied luggage was on it's plane; not one person has ever reconciled all the passengers and luggage on the Erac Printout - The system as it was at Frankfurt is unverifiable and full of errors. )
Did you get that? Clothes from Malta, suitcase bomb seemingly from Malta to London via Frankfurt, Megrahi at Luqa airport on the morning of interest.
Or if you prefer: suitcase from Malta seemingly transferred at Frankfurt from a Malta flight to London, Malta clothes in the suitcase, Megrahi in Malta on the morning of interest.
A much better article by David Wolchover:Exploding Lockerbie Part 1 - Conviction by Feedback Loop
Now all of this may be construed by some as 'arguing over the minutaie'
Quite. Indeed, even. Yet it's exactly this that sent a demonstrably innocent man to the gaol. A man who is still reviled by the non-thinking or ill-informed as The Lockerbie Bomber. If the prosecution have come up with any evidence since that proves the case against Mr Megrahi beyond reasonable doubt I'll eat your hat. Releasing Mr Megrahi wasn't a mistake, finding him guilty was. There's far too many wee and inconsequential men, with their wee and inconsequential careers at stake, able to man-up enough and admit as much.