Abu Agila Masud (second left) sits behind bars during a hearing at a courtroom in Tripoli November 16, 2014. He is said to have told investigators how he positioned the device near metal in the suitcase to avoid detection by airport scanners
Abu Agila Mohammad Masud was charged by the US two years ago for the Lockerbie bombing. He had previously been held in Libya for his alleged involvement in a 1986 attack on a Berlin nightclub.
Only one individual has so far been prosecuted for the bombing of Pan Am flight 103 on December 21, 1988, which claimed 270 lives.
Former Libyan intelligence officer Abdelbaset Ali Mohmet al-Megrahi spent seven years in a Scottish prison after his conviction in 2001.
He died in Libya in 2012, always maintaining his innocence.
"The families of those killed in the Lockerbie bombing have been told that the suspect Abu Agila Mohammad Masud Kheir Al-Marimi ... is in US custody," a spokesperson for Scotland's Crown Office and Procurator Fiscal Service 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."