Prosecutors made it clear that they will not seek the death penalty against the Tunisian-Libyan man. Rather, he is threatened with life imprisonment for his alleged involvement in the bomb attack on a passenger plane of the US airline Pan Am with 270 deaths. Attorney General Merrick Garland said it was an "important step in our mission to honor victims and seek justice on behalf of their families."

Scottish prosecutors announced on Sunday that Masud was in US custody. The circumstances under which he was taken into custody by the United States initially remained unclear. He is said to have been in detention in Libya.

Masud has now been flown to the USA and processed by the US authorities in the city of Alexandria, which borders Washington. The first court hearing was then held on Monday afternoon. An indictment that had previously been kept secret was also published.

The US judiciary had made an investigation against Masud public at the end of 2020. At the end of November of this year, Masud was finally formally indicted by a so-called grand jury.

The former Libyan secret agent is said to have been one of the most important bomb manufacturers of the former ruler Muammar al-Gaddafi. He is also believed to have been involved in the 1986 attack on the La Belle nightclub in Berlin, which killed two US soldiers and a Turkish woman.

Masud has been under investigation in the USA and Scotland for years because of the Lockerbie attack. The ex-agent is said to have built the bomb for the attack on Pan Am Flight 103, which killed 270 people 34 years ago, including 190 US citizens. The plane was en route from London to New York on December 21, 1988 when it exploded over the small Scottish town of Lockerbie 38 minutes after take-off.

So far, only one person has been convicted of the Lockerbie attack: in 2001, former Libyan intelligence officer Abdelbaset Mohamed al-Megrahi received a long prison sentence, but was released from a Scottish prison in 2009 on medical grounds and died in 2012 in the Libyan capital, Tripoli. He maintained his innocence until his death.