20 May 2012
Last updated at 17:20
On 21 December 1988, 270 people were killed when Pan Am Flight 103 blew up over the town of Lockerbie, in southern Scotland - the deadliest terrorist incident ever to have taken place on British soil.
In November 1991, Abdelbaset al-Megrahi, a Libyan intelligence agent, was indicted by the US and Scottish authorities.
Megrahi, seen here in a 1998 TV interview, always denied any role in the Lockerbie bombing. In 2001, he and another Libyan went on trial at a special court in the Netherlands.
His co-accused was acquitted but Megrahi - seen here at his trial - was convicted in 2002 and sentenced to life in prison. He appealed twice against his conviction but dropped his second appeal just two days before he was released from prison on compassionate grounds.
The British and American authorities welcomed his conviction, but some of the victims' relatives came to believe Megrahi was not the bomber. Dr Jim Swire, whose daughter Flora was killed, described Megrahi's death as a "very sad event".
In August 2009, the Scottish government freed Megrahi on compassionate grounds and allowed him to return to Tripoli. He was suffering from cancer; doctors estimated he had less than three months to live.
When he landed in Tripoli, Megrahi received a hero's welcome from crowds gathered at the airport. Saif al-Islam Gaddafi, son of Libyan leader Col Muammar Gaddafi, escorted him off the plane.
The Scottish government's decision to free Megrahi sparked outrage on both sides of the Atlantic. Scottish Justice Secretary Kenny McAskill defended his decision, but US President Barack Obama called it a "mistake".
After his return to Tripoli, Megrahi was rarely seen in public. However, he was filmed at a government rally in July 2011, as the Nato-backed uprising against Col Gaddafi was gathering strength.
By the time this picture was taken, in October 2011, Megrahi had been free for two years - seriously undermining doctors' predictions in August 2009 that he would be dead within three months.
But on 20 May, his relatives announced Megrahi had died at his home in Tripoli (pictured). UK Prime Minister David Cameron said it was a day to remember the victims of Lockerbie, but said Megrahi should never have been released.