The trial of a Libyan man over the Lockerbie bombing has been postponed for a third time, after new evidence on the 37-year-old case came to light three days ago.
Jury selection was due to get under way in Washington DC on Wednesday but the BBC understands a new start date has been set for January next year.
Lawyers acting for Abu Agila Mohammad Kheir Al-Marimi said "newly discovered evidence" previously unknown to the defence and prosecutors from the US government emerged on Friday 21 August.
Al-Marimi has denied building the bomb that destroyed Pan Am Flight 103 on 21 December 1988, killing 270 people.
His lawyers told the court: "Constitutional and ethical obligations require the defence to investigate this development."
They said they met Al-Marimi on Sunday and he agreed that they should ask for the postponement.
The trial judge, Dabney Friedrich, has agreed that the start date should be set aside, underlining the potential importance of the new evidence.
She would have been extremely reluctant to allow an 11th hour postponement after months of preparation and marathon pre-trial legal battles.
For the relatives of those who died and Al-Marimi himself, this latest delay means a verdict might not come until next spring.
It is yet another stunning development in a saga that has witnessed countless twists and turns over nearly four decades.
Pan Am 103 was flying from Heathrow to New York when the bomb exploded in its forward hold, breaking the plane apart at 31,000 feet.
All 259 passengers and crew on board were killed. Another 11 people died in Lockerbie when the wreckage fell on their homes.
Of the victims, 190 were American and 43 from the UK.
Nearly four decades later, the bombing remains the worst terror attack and mass murder in British history.
Al-Marimi has been in US custody since 2022 and was originally due to stand trial in May 2025.
That date was set aside following a joint request from the prosecution and defence, who cited the complexity of the case and Al-Marimi's ill health.
The trial was pencilled in for April this year but was called off again, after the defence asked for more time to prepare.
The Lockerbie bombing has been the subject of a joint Scottish-US investigation since December 1988.
Prosecutors from the Crown Office and detectives from Police Scotland were due to travel to Washington to attend the case, and Scottish witnesses were expected to be among the first to give evidence at the trial.
Laura Buchan, head of the Lockerbie investigation team at the Crown Office and Procurator Fiscal Service said: "I recognise that this adjournment will be disappointing for the families and for those who have followed this case over many years.
"As the matter remains before the court, it would not be appropriate to comment on the reasons for the adjournment. Although these proceedings are being led by the United States authorities, Scottish prosecutors and police officers remain fully committed to supporting the pursuit of justice."
Campaigner Kara Weipz, who is president of the Victims of Pan Am Flight 103 group, said she was "floored" when she received the news that the trial had been postponed.
She told the BBC's Radio Scotland Breakfast programme that she would pray that older relatives of victims would "remain healthy" so they can see the trial eventually take place.
She said: "It's always been my goal for as many family members to be able to witness this trial as possible and to gain more of the truth.
"If that's what this evidence brings, that's what the families have been fighting for for almost four decades - we want the truth, we want to know what happened - and if that's what this brings then this time will be worth it."
A grandfather in his 70s, Al-Marimi has been accused of carrying out the attack along with two Libyans who faced a Scottish court in May 2000.
Three judges heard the case at Camp Zeist, a former US air force base in the Netherlands.
After eight months, they ruled the atrocity was an act of state sponsored terrorism carried out by members of the Libyan intelligence service.
The judges convicted one of the Libyans, Abdulbasset Al-Megrahi, of mass murder and jailed him for life.
He died from cancer in 2012, after being freed on compassionate grounds by the Scottish government.
The Scottish Criminal Cases Review Commission twice referred Megrahi's case to the appeal court but the conviction was upheld.
The second Libyan, Al Amin Khalifah Fhimah was acquitted and returned home to a hero's welcome in Tripoli.
The US government says Al-Marimi admitted bombing the plane along with Megrahi and Fhimah when he was questioned in a Libyan detention facility in 2012.
The alleged confession was handed to Scottish investigators in 2017 and is now central to the prosecution case.
Al-Marimi has claimed the confession is false and was made under duress, but judge Friedrich ruled it can be admitted as evidence at the trial.
