Story highlights 270 people were killed when Pan Am Flight 103 exploded over the Scottish town in 1988

Scotland's chief public prosecutor has written to Libyan authorities asking for assistance

London (CNN) Two Libyans have been identified as suspects in the bombing of Pan Am Flight 103 over Lockerbie, Scotland, nearly 27 years ago, Scottish and U.S. officials say.

They have asked for Libya's help to interview them.

The 259 people on New York-bound Pan Am Flight 103 and 11 people on the ground were killed when it crashed 38 minutes after takeoff from London on December 21, 1988.

Afterward, U.S. and British investigators found fragments of a circuit board and a timer and ruled that a bomb, not mechanical failure, caused the explosion.

Libyan Abdelbeset Ali Mohmed al Megrahi was the only person convicted in connection with the bombing.