(NewsNation) — The alleged bombmaker in the downing of Pan Am flight 103 is in U.S. custody, an arrest Richard Marquise said was “a long time coming.”

Marquise is a retired FBI agent who oversaw the multiagency task force that investigated the 1988 bombing that killed all 259 aboard and 11 people on the ground in Lockerbie, Scotland.

The Justice Department announced Sunday it arrested Abu Agila Mohammad Mas’ud Kheir Al-Marimi, a former Libyan intelligence officer they say made the bomb. Mas’ud was charged in 2020 for his alleged role in the plot that killed 190 Americans.

Marquise joined “Rush Hour” to discuss the investigation. Watch his interview above.