The suspect, identified by the Wall Street Journal as Abu Agila Mohammad Masud, is a Libyan intelligence official whom the Journal reported is in custody in Libya and will be extradited to the United States to stand trial.
The case, to be unveiled in the coming days, would mark the second time Attorney General William Barr has overseen charges in connection with the bombing.
During Barr's first stint as attorney general under President George H.W. Bush, the Justice Department indicted two Libyan Intelligence Agency operatives - Abdel Basset Ali Al-Megrahi and Lamen Khalifa Fhimah - for building a plastic bomb with a timer, hiding it inside a suitcase and planting it on an Air Malta flight.
The suitcase was eventually transferred to Pan Am Flight 103.
"We will not rest until all those responsible are brought to justice. We have no higher priority," Barr said in 1991, at the time the indictment was unveiled. Parallel charges were also filed against the men in Scotland.
Since then, only one person has been brought to justice.
Megrahi was found guilty in Scotland of the Lockerbie bombing in 2001. He was freed in 2009 on compassionate release grounds and returned to Libya because he had terminal cancer. He died in 2012.
His release back to Libya at the time infuriated the Justice Department, which had the indictment against him pending and was still investigating the bombing.
The 32-year anniversary of the bombing of Pan Am Flight 103 - in which 190 Americans died - will be on Monday.A Justice Department spokesman declined to comment on the soon-to-be-unsealed case.