. >> dornstein: the la belle disco? >> la belle disco. >> it was around 2:00 a.m. when the bomb went off in the crowded la belle discotheque. police say there were about 500 people inside, many of them off-duty u.s. soldiers. >> dornstein: the cycle of revenge that ended in lockerbie likely began here in germany, when u.s. servicemen at a berlin nightclub were attacked in april of 1986. >> the evidence is now conclusive that the terrorist bombing of la belle discotheque was planned and executed under the direct orders of the libyan regime. orders were sent from tripoli... >> dornstein: whatnterested me were clues that several of the men on my list were also involved in the disco bombing. said rashid seems to have led the attack, but was never prosecuted. but there was another man who worked for him on the disco bombing, and this man was would ultimately become the most significant figure in my search for answers on lockerbie. >> police have arrested a libyan man suspected in a 1986 bombing of a discotheque in berlin-- a

. >> a bomb went off in the la belle disco. >> would that surprise you, that the bomb expert in la belles also involved in lockerbie? >> filmmaker ken dornstein closes in on a known bomb maker he suspects was involved in the death of his brother. >> go to pbs.org/frontline for more about the search for answers in the bombing of pan am flight 103. >> lockerbie's still an open case that somebody has assigned to him. >> explore an interactive guie to filmmaker ken dornstein's investigation into the attack. >> we got part of the conspiracy, but only a small part. >> connect to thfrontline community on facebook and twitter. visit us on youtube for even more original frontline reporting. and if stories like this matter to you, then sign up for our newsletter at pbs.org/frontline. >> frontlinis made possible by contributions to your pbs station from viewers like you. thank you. and by the corporation for public broadcasting. major support for frontliis provided by the john d. and catherine t. macarthur foundation, committed to building a more just, verdant and peaceful world. more information i