A man accused of making the bomb that blew up a flight over Lockerbie in Scotland in 1988 is in custody, Scottish and U.S. law enforcement officials say.

The attack on Pan Am flight 103 killed all 259 people on board and 11 people on the ground, and is the deadliest ever militant attack in Britain.

A U.S. Justice Department official confirmed on Sunday that Abu Agila Mohammad Mas’ud Kheir Al-Marimi had been taken into custody.

He is expected to make his initial court appearance in a federal court in Washington D.C.

A spokesperson for Scotland’s Crown Office and Procurator Fiscal Service said the families of those killed in the Lockerbie bombing had been informed.

In 2001 Libyan intelligence operative Abdel Baset Ali al-Megrahi was found guilty of the bombing and jailed for life.

He was later released because he was suffering from cancer and died in 2012.

Scottish prosecutors have maintained that Megrahi did not act alone.

In 2020 the United States unsealed criminal charges against Mas’ud, a suspected third conspirator, adding that he had worked as a technical expert in building explosive devices.