The 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 made his initial appearance in U.S. District Court in Washington on Monday to face federal charges.

An indictment of Abu Agila Mohammad Mas'ud Kheir Al-Marimi was unsealed Monday, nearly 34 years after the attack that killed 259 people in the air and 11 on the ground. Among the 190 Americans on board were 35 Syracuse University students flying home for Christmas after a semester abroad.

The Justice Department announced Sunday that Mas'ud had been taken into U.S. custody. In 2020, the department made public a criminal complaint charging Mas’ud with destruction of aircraft resulting in death, and destruction of a vehicle used in foreign commerce by means of an explosive resulting in death.

“Nearly 34 years ago, 270 people, including 190 Americans, were tragically killed in the terrorist bombing of Pan Am Flight 103. Since then, American and Scottish law enforcement have worked tirelessly to identify, find, and bring to justice the perpetrators of this horrific attack. Those relentless efforts over the past three decades led to the indictment and arrest of a former Libyan intelligence operative for his alleged role in building the bomb used in the attack,” said U.S. Attorney General Merrick B. Garland. “The defendant is currently in U.S. custody and is facing charges in the United States. This is an important step forward in our mission to honor the victims and pursue justice on behalf of their loved ones.”

A breakthrough in the investigation came when U.S. officials in 2017 received a copy of an interview that Mas'ud, a longtime explosives expert for Libya’s intelligence service, had given to Libyan law enforcement in 2012 after being taken into custody following the collapse of the government of the country’s leader, Col. Moammar Gadhafi.

In that interview, U.S. officials said, Mas'ud admitted building the bomb in the Pan Am attack and working with two other conspirators to carry out the attack. He also said the operation was ordered by Libyan intelligence and that Gadhafi thanked him and other members of the team after the attack, according to an FBI affidavit filed in the case.

“Today’s action is another crucial step in delivering justice for the victims of the senseless terrorist attack on Pan Am Flight 103,” said Deputy Attorney General Lisa O. Monaco. “Our thoughts are with the victims’ families, whose tireless work to honor the lives and legacies of their loved ones has inspired the Department of Justice and our Scottish partners throughout our investigation for the last 34 years. Let this be a reminder that the men and women of the Department of Justice will never forget the loss of innocent lives or waver in our commitment to holding terrorists accountable – no matter how long it takes.”

The bombing laid bare the threat of international terrorism more than a decade before the Sept. 11, 2001, attacks. It produced global investigations and punishing sanctions while spurring demands for accountability from victims of those killed. Several victims described as surreal the news that Mas'ud was finally in American custody.

“It was quite a moment," said Kara Monetti Weipz, sister of victim Rick Monetti, a Syracuse University student, and the president of Victims of Pan Am Flight 103. “It was unbelievable that it was really happening after all these years, and especially after the last two years.”

Outside the courthouse Monday, Paul Hudson carried a photograph of his daughter, Melina, a 16-year-old student who was returning for the Christmas holidays from an exchange program in England. He recalled how, after the crash, her belongings were scattered around the Lockerbie countryside. The family did get back her passport and her notebook.

“And the notebook had, on the cover, the quote ‘No one dies unless they’re forgotten,’ and I've tried to live by that,” he said. Remembrances of his daughter are an “everyday thing” and “this time of year, it gets stronger.”