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Within the tight circles of terrorism experts, Thurman is a legend. In 1990 he solved what everyone thought was an almost perfect crime, figuring out who destroyed Pan Am Flight 103 over Lockerbie, Scotland on Dec. 21, 1988. Thurman matched a fragment of a circuit board from the bomb's timer to an identical circuit board, which was part of a timer the CIA had recovered from an intact, unexploded bomb seized in Togo in 1986. Thurman's amazing command of detail led to a Zurich electronics firm that admitted selling 20 such timers to the Libyan regime. The U.S. was then able to charge that Libyan intelligence agents had tagged a brown "bomb bag" containing the radio with stolen Air Malta tags and placed it on an Air Malta Flight KM-190 routed to Frankfurt, whence it eventually was loaded onto Pan Am Flight 103. It was detonated by a simple timing device. Libya has been under U.N. economic sanctions since April 1992. Last week Thurman was on the scene in Long Island as parts of the TWA plane were dragged out of the surf. He and his lab team will conduct microscopic examinations of pieces of the plane's skin and infrastructure, looking for metal damage characteristic of a powerful bomb blast. "An explosion generates temperatures and velocities of detonation that are far greater than those encountered in a crash scenario due to mechanical failure," says Chris Ronay, Thurman's predecessor as chief of the FBI bomb unit. "You get torturing, feathering, pitting and tearing in metal that's entirely different from damage inflicted by a fire or a fall."
The lab analysis can determine which way metal was torn and whether it was ripped by the compression of a blast or by being struck by a heavy object. Rivets that loosened or popped off will be examined to determine the direction and force of the pressures to which they were subjected. FBI lab chemists will do a chemical analysis of the metal to see if there are embedded nitrates, the molecular building blocks of all known explosives.
FBI agents know that weapons need not be highly sophisticated to be lethal. "There's a great danger in looking for the most sophisticated plan," says Harry Brandon, the FBI's former deputy assistant director in charge of international terrorism and a supervisor of the Pan Am 103 case. "We tend to think terrorists are invincible, that they're smart as hell, and often they're not." Just lucky. "All you need is a clock and an explosive that's powerful enough," says Ronay. On Pan Am Flight 103, the bomb was the size of a coffee cup, but it happened to be placed near the skin of the plane, where it broke through the fuselage and weakened the frame of the aircraft, causing the plane to break up. "If it had been inboard," says Ronay, "it might not have done that kind of damage. Luggage makes a good buffer." Terrorists may have been lucky with TWA Flight 800 as well.
THE LEGACY OF FEAR