A Libyan intelligence official accused of making the bomb that brought down Pan Am Flight 103 over Lockerbie, Scotland, in 1988 in an international act of terrorism has been taken into U.S. custody and will face federal charges in Washington, the Justice Department said Sunday.

The arrest of Abu Agela Masud Kheir Al-Marimi is a significant milestone in the decades-old investigation into the attack that killed 259 people in the air and 11 on the ground. American authorities in December 2020 announced charges against Masud, who was in Libyan custody at the time. Though he is the third Libyan intelligence official charged in the U.S. in connection with the attack, he would be the first to appear in an American courtroom for prosecution.

The New York-bound Pan Am flight exploded over Lockerbie less than an hour after takeoff from London on Dec. 21, 1988. Citizens from 21 different countries were killed. Among the 190 Americans on board were 35 Syracuse University students flying home for Christmas after a semester abroad.

The bombing laid bare the threat of international terrorism more than a decade before the Sept. 11 attacks. It produced global investigations and punishing sanctions while spurring demands for accountability from victims of those killed.