The US had announced charges against Abu Agila Masud two years ago, and Scotland’s Crown Office and Procurator Fiscal Service (COPFS) said he was now in custody.

“The families of those killed in the Lockerbie bombing have been told that the suspect Abu Agila Mohammad Mas’ud Kheir Al-Marimi (“Mas’ud” or “Masoud”) is in US custody,” a spokesman for the COPFS said.

“Scottish prosecutors and police, working with UK government and US colleagues, will continue to pursue this investigation, with the sole aim of bringing those who acted along with al-Megrahi to justice.”

The COPFS said it would be inappropriate to comment further on a live criminal investigation.

The BBC first reported Masud’s arrest.

The bomb on board the Boeing 747 en route to the US killed all 259 people on board and 11 on the ground, the deadliest ever militant attack in Britain.

In 1991, two other Libyan intelligence operatives were charged in the bombing: Abdel Baset Ali al-Megrahi and Lamen Khalifa Fhimah.

Megrahi was found guilty of the bombing, and was jailed for life in 2001. He was later released because he was suffering from cancer, and died in 2012.

Fhimah was acquitted of all charges, but Scottish prosecutors have maintained that Megrahi did not act alone.

In 2020, the US unsealed criminal charges against Masud, a suspected third conspirator, adding that he had worked as a technical expert in building explosive devices.