In 1988, a bomb killed 270 people after it blew up Pan Am flight 103 over the Scottish town of Lockerbie. The man accused of making the bomb, Abu Agila Masud, is now in US custody.
What happened?
On December 2, 1988, a Pan Am Boeing 747 bound for New York from London's Heathrow Airport exploded less than after an hour after it departed.
The attack destroyed the aircraft, which was carrying citizens from 21 different countries. Most of them were from the United States (190) and the United Kingdom (32).
All 243 passengers and 16 crew members were killed, as well as 11 Lockerbie residents on the ground when a wing section hit a house at more than 800 kph, creating a 47-metre crater.
To this day the bombing is the deadliest terrorist attack ever carried out on British soil.
Who was responsible?
In 1991, the US charged two Libyan intelligence officers with planting the bomb on board the plane.
But the country's leader at the time, Moamar Gaddafi, refused to turn them over.
In 1999, after long negotiations, Libya agreed to surrender the pair for prosecution by a panel of Scottish judges sitting in the Netherlands.
One of the men, Abdel Baset Ali al-Megrahi, was convicted and given a life sentence. The other man, Lamen Khalifa Fhimah, was found not guilty.
In 2009, Al-Megrahi was released on humanitarian grounds by Scottish officials after he had been diagnosed with prostate cancer. He died three years later in Libya.
The families of those who had been killed in the bombing later brought a lawsuit against the Libyan government, demanding they be held accountable.
In 2003, Libya agreed to a settlement, formally accepting responsibility for the attack, renouncing terrorism and paying compensation to the families.
Despite rapprochement from with the US government, the pursuit of others that were responsible for the bombing largely stalled until after Gaddafi was ousted from power in 2011.
How did investigators find Masud?
After Gaddafi's fall, Abu Agila Masud, a longtime explosives expert for Libya's intelligence service, was taken into custody by the countries own law enforcement.
In 2017, US officials received a copy of the interview with Masud done by Libyan authorities soon after his arrest.
That interview, US officials said, showed Masud admitting to building the bomb used in the Pan Am attack and working with the two men charged earlier to plant it on the plane.
He said that the operation had been ordered by Libyan intelligence, and that dictator Gaddafi had thanked him and others after the attack was carried out, according to an FBI affadavit.
In late 2020, the US Justice Department announced charges against Masud.
Two years after those charges were announced, Masud was taken into custody, Scotland's Crown Office and Procurator Fiscal Service (COPFS) said on Sunday.
US officials did not state how Masud came to be detained, but in late November local Libyan media reported that he had been kidnapped by armed men from his residence in Tripoli.
