The US is expected to unseal charges against another suspect in the 1988 Lockerbie airline bombing which killed 270 people, US media is reporting.
A Libyan intelligence officer identified as Abu Agila Mohammad Masud is in custody in Libya and will be extradited to the US to stand trial, the Wall Street Journal said.
The majority of the victims on the London to New York flight were American citizens.
In 2001, Libyan intelligence officer Abdelbaset al-Megrahi was the only person convicted of the attack on Pan Am flight 103 after it exploded over the Scottish town of Lockerbie.
He was given a life sentence, but Scottish authorities released him on humanitarian grounds in 2009 when he was diagnosed with prostate cancer. He later died in Tripoli.
The new case, to be unveiled in the coming days, is likely to be of special significance to the US Attorney General William Barr – who is leaving his position next week – as it is the second time he has overseen charges in connection with the bombing.
He held the same job when the Justice Department indicted Megrahi and a second Libyan, Lamen Khalifa Fhimah, for building a plastic bomb with a timer before hiding it inside a suitcase and planting it on an Air Malta flight.
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The suitcase was then transferred to Pan Am flight 103.
At the time the indictment was unveiled in 1991, Mr Barr said: “We will not rest until all those responsible are brought to justice. We have no higher priority.”
In 1992, the UN Security Council imposed arms sales and air travel sanctions against Libya to force Colonel Muammar Gaddafi, the country’s then leader, into surrendering the two suspects.
Fhimah was acquitted, but Megrahi was jailed for life with a minimum term of 27 years.
The sanctions were later lifted after Libya agreed to a $2.7bn (£1.95bn) compensation deal with the victims’ families.