Timeline: Lockerbie bombing
The case of Libyan Abdelbaset Ali al-Megrahi has been a complex one since the day he was indicted on 270 counts of murder in November 1991.
Ten years later he was found guilty of killing the people who died when Pan Am Flight 103 exploded over the Scottish town of Lockerbie.
Megrahi, who has always proclaimed his innocence, unsuccessfully appealed against his conviction. But he was subsequently allowed to return home after it emerged that he had terminal cancer, and he died in 2012.
Here are some of the key moments in the story of the bombing.
15 October 2015
Scottish prosecutors request permission from the Libyan authorities to interview two suspects over the Lockerbie bombing.
3 July 2015
Scottish judges rule that relatives of the victims should not be allowed to pursue an appeal on Megrahi's behalf.
Families argued they should have the right to carry forward the miscarriage of justice appeal for Megrahi.
20 December 2014
Scotland's top prosecutor, Lord Advocate Frank Mulholland, reaffirms his belief that Megrahi is guilty of the Lockerbie bombing and says no Crown Office investigator or prosecutor ever raised concerns about the evidence used to convict him.
He also pledges to continue tracking down Megrahi's accomplices.
20 May 2012
Abdelbaset al-Megrahi dies at his home in Tripoli, aged 60.
20 October 2011
Libyan leader Colonel Gaddafi is overthrown by an uprising in Libya, and is killed by rebels.
29 August 2011
Megrahi falls into a coma at his Tripoli home with CNN reporting he appeared to be "at death's door".
24 August 2009
The Scottish Parliament is recalled to discuss the release of the Lockerbie bomber.
Justice Secretary Kenny MacAskill faces questioning over his decision from MSPs but says he stands by his decision and will "live with the consequences".
20 August 2009
The Scottish government releases Megrahi on compassionate grounds. He returns home to Libya aboard a jet belonging to Libyan leader Muammar Gaddafi.
18 August 2009
Judges accept an application by the Lockerbie bomber to drop his second appeal against conviction.
The permission of the High Court in Edinburgh was required before the proceedings could be formally abandoned.
25 July 2009
Megrahi asks to be released from jail on compassionate grounds due to his illness.
21 December 2008
Relatives of the 270 people killed in the Lockerbie bombing mark the 20th anniversary of the tragedy.
14 November 2008
A court rules that Megrahi, will remain in jail while he appeals against his conviction.
31 October 2008
The father of one of the victims of the Lockerbie bombing reiterates his call for Megrahi to be released.
Jim Swire, whose daughter was killed, criticised the slow appeal process faced by the man convicted of the attack and said the question of whether Megrahi should be released was one of "common humanity".
21 October 2008
Megrahi's lawyer reveals the 56-year-old former Libyan intelligence agent has been diagnosed with "advanced stage" prostate cancer.
28 June 2007
The Scottish Criminal Cases Review Commission, which has been investigating the case since 2003, recommends Megrahi is granted a second appeal against his conviction.
24 November 2003
Megrahi is told he must serve at least 27 years in jail.
His sentence was increased after a change in the law meant he had to again come before the Scottish courts so that the punishment period could be set.
14 August 2003
Lawyers acting for families of the Lockerbie bombing victims say they have reached agreement with Libya on the payment of compensation.
The deal to set up a $2.7bn (£1.7bn) fund was struck with Libyan officials after negotiations in London.
15 March 2002
Megrahi spends his first night at a prison in Glasgow after being flown by helicopter to HMP Barlinnie.
14 March 2002
Megrahi loses his appeal against the conviction.
31 January 2001
Abdelbaset Ali al-Megrahi is found guilty of murder after the historic trial under Scottish law in the Netherlands.
The judges recommend a minimum of 20 years "in view of the horrendous nature of this crime".
Megrahi's co-accused, Al Amin Khalifa Fhimah, is found not guilty and told he is free to return home.
3 May 2000
The trial of Abdelbaset Ali al-Megrahi, 48, and Al Amin Khalifa Fhimah, 44, opens at Camp Zeist, a specially convened Scottish court sitting in the Netherlands.
5 April 1999
The suspects are taken into Dutch custody after flying from Tripoli to an airbase near the Hague and are formally charged with the bombing.
UN sanctions against Libya are suspended as agreed.
Britain and the United States propose trying the suspects in the Netherlands under Scottish law.
15 April 1992
The UN Security Council imposes sanctions on air travel and arms sales over Libya's refusal to hand the suspects over for trial in a Scottish court.
13 November 1991
US and British investigators indict Libyans Abdelbaset Ali al-Megrahi and Al Amin Khalifa Fhimah on 270 counts of murder, conspiracy to murder and violating Britain's 1982 Aviation Security Act.
The men were accused of being Libyan intelligence agents.
21 December 1988
Pan Am Flight 103 from London to New York explodes 31,000 feet over Lockerbie, 38 minutes after take-off from London.
The 259 people on board the Boeing 747 are killed, along with 11 people on the ground.