(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.