(CNN)Here's a look at the bombing of Pan Am Flight 103.
On December 21, 1988, Pan Am Flight 103 exploded 31,000 feet over Lockerbie, Scotland, 38 minutes after takeoff from London.
Two hundred fifty-nine people on board the New York-bound Boeing 747 were killed, along with 11 people on the ground.
Afterward, United States and British investigators found fragments of a circuit board and a timer, and ruled that a bomb, not mechanical failure, caused the explosion.
Libyans Abdelbeset Ali Mohmed al Megrahi and Al Amin Khalifah Fhimah were tried for the bombing. Al Megrahi was found guilty, while Fhimah was found not guilty.
The suspects were tried in a Scottish court at Camp Zeist, a former US air base 20 miles south of the Dutch capital of Amsterdam. The Dutch declared 30 acres of the 100-acre base Scottish territory so that the trial could be held in a neutral country as al Megrahi, Fhimah and Libyan leader Moammar Gadhafi had wanted. There was no jury; three Scottish judges presided, with a fourth as reserve.
Authorities said al Megrahi and Fhimah manufactured the bomb out of Semtex plastic explosives, concealed it in a Toshiba cassette recorder, hid the recorder in a Samsonite suitcase and slipped the suitcase aboard an Air Malta flight headed from Malta to Frankfurt, Germany. The unaccompanied bag is believed to have been transferred to a Pan Am flight to London and then to Flight 103.
The CIA and FBI said the suspects, employed by Libyan Arab Airlines in Malta, were also Libyan intelligence agents. Lesser charges of conspiracy to murder and violating Britain's 1982 Aviation Security Act were dropped.
Over three years, investigators from the United States, Britain, Germany and other countries questioned more than 15,000 people in more than 30 countries and collected thousands of pieces of evidence.
The death penalty is not permitted under Scottish law. There is no prescribed punishment for a conviction of conspiracy to murder. Any punishment is at the discretion of the court. Life imprisonment is the prescribed punishment for murder or contravention of the Aviation Security Act 1982. Any prison sentence would be served in Scotland.
December 21, 1988 - Pan Am Flight 103 explodes 31,000 feet over Lockerbie, Scotland, 38 minutes after takeoff from London. The 259 people on board the New York-bound Boeing 747 are killed, along with 11 people on the ground.
July 1990 - The British Civil Aviation Authority's Air Investigation Branch officially reports that an explosive device caused the crash of Pan Am Flight 103.
November 13, 1991 - US and British investigators indict Libyans al Megrahi and Fhimah on 270 counts of murder, conspiracy to murder and violating Britain's 1982 Aviation Security Act. The men a