Yes, Abdelbaset al-Megrahi—looks like mass55th beat me to it.
Interesting that Barr is leaving on or near the 32nd anniversary of the Lockerbie bombing, since he was also the AG back then.
“...The announcement of a prosecution against an additional individual would carry personal significance for Attorney General William Barr, who is leaving the position next week but held the same job when the Justice Department nearly 30 years ago revealed criminal charges in the U.S. against the two Libyans. Monday is the 32nd anniversary of the bombing.”
Barr, in a quote from back then:
“This investigation is by no means over. It continues unabated. We will not rest until all those responsible are brought to justice,” Barr said at a 1991 news conference announcing the charges. “We have no higher priority.”
The head of the Justice Department’s criminal division at the time was Robert Mueller, who went on to serve as FBI director and as special counsel in charge of the investigation into ties between Russia and the 2016 Trump campaign.