Abu Agila Masud is accused of building the explosive used in the Lockerbie bombing, but has pleaded not guilty in a US court. The man is alleged to have been involved in the disaster which took place in 1988.
Masud is charged with two counts of destruction of an aircraft resulting in death and one count of destruction of a vehicle resulting in death.
He pleaded not guilty to all three charges in a federal court in Washington.
All three of the charges are punishable with a sentence of up to life imprisonment, the death penalty or a fine of up to $250,000 (£206,000).
However, in a previous hearing in December it was stated that Masud would not face the death penalty because the bombing occurred before the specific charges which he faces carried a possible penalty of capital punishment.
READ MORE: King Charles uses ‘ritual’ to welcome Zelensky to the UK
He was later released because he was suffering from cancer and he died at his home in Tripoli in 2012.
Mr Fhimah was acquitted of all charges, but Scottish prosecutors have said that Megrahi did not act alone.
On December 21, 1988, the Pan Am Flight 103 set off from London to New York, but just 40 minutes into the flight, as the plane made its way over Lockerbie, Scotland, it exploded, killing everyone on board.
The Boeing 747 was flying at around 31,000 feet and carrying 259 people, including babies, when it disappeared from the radar.
It was at the time the worst airline bombing the world had ever seen, and remains the UK’s deadliest terrorist incident.
Not only were all those on board killed, but 11 lives were lost on the ground, with 21 buildings obliterated.