In December 1988, Britain's worst terrorist attack left 270 people dead.
THE CONSPIRACY FILES
The Conspiracy Files: Lockerbie
Sunday, 31, August, 2008
2100 BST, BBC Two
After a massive police and FBI investigation, a Libyan intelligence officer was found guilty of mass murder, but he has now been granted a second appeal against his conviction.
Twenty years on, will the full story of Pan Am flight 103 finally emerge?
The Conspiracy Files follows the trail of evidence from the Middle East, through Europe and on to North America, investigating the tangled web of claims and counter-claims surrounding the Lockerbie bombing.
The first thread the programme follows is that of the mystery caller who tipped off the US Embassy in Helsinki two weeks before the crash happened, that a bomb would be planted on a flight from Frankfurt.
The programme talks to the American agent who took the call, tracks down the man who is believe to have made it and also interviews the Palestinian who was investigated by the police and exonerated as a result.
The second thread leads to Ahmed Jibril, leader of the Palestinian extremist faction PFLP-GC. In a rare interview, he denies the allegation that this group were behind the attack, backed by Iran.
The programme then looks at the theory put forward by Juval Aviv, an investigator hired by Pan Am, that rogue CIA agents allowed the bomb to be planted in a top secret drugs operation which went horribly wrong.
The Conspiracy Files also examines the prosecution case that Libya carried out the attack.
It has always been supposed that the motive was revenge for an American attack on Tripoli in 1986. Among those killed was Colonel Gaddafi's four-year-old adopted daughter Hannah.
But the programme also examines allegations that the Libyans were set up.
It examines allegations that evidence implication Libya was planted or tampered with.
This is categorically denied by the leader of the FBI's Lockerbie task force, Dick Marquise, who spoke at some length to The Conspiracy Files. "I can promise you it did not happen," he said.
Many believe that Abdelbaset Ali Mohamed al-Megrahi, who was convicted of the murders was a fall guy. If he was responsible for placing the bomb, he was a pawn in a much bigger political game.
Martin Cadman, whose son Bill died in the disaster, told The Conspiracy Files: "The truth has not come out. I think the investigation found out what it was told to find."
Producer/Director: Guy Smith
Executive Producer: Sam Anstiss