Lockerbie

In 1988, the families of those on board flight Pan Am 103 learn that the plane has crashed over Lockerbie, Scotland, killing 270. A terrorism investigation begins. (1 of 4)

The prime suspects for the bombing of flight Pan Am 103 are a Palestinian terror group funded by Iran. But Scottish and FBI investigators are led elsewhere. (2 of 4)

A Libyan double agent provides the evidence needed to bring the two suspects to court. The trial gets underway, but a key witness changes his story. (3 of 4)

A shock verdict leaves the families unsatisfied. Doubt is cast on the court's decision, and 34 years after the bombing, a new suspect is taken into US custody. (4 of 4)