SCOTLAND'S former justice secretary has urged the Lord Advocate to seek an update on a fourth Lockerbie suspect when she travels to the United States.

As the 34th anniversary of the bombing approaches on Wednesday Dorothy Bain KC is travelling to the US this week to meet with state prosecutors to discuss the case and attend commemoration ceremonies for victims of the bombing.

Her visit follows the announcement last Sunday by Washington that Abu Agila Mohammad Masud Kheir Al-Marimi had been detained in the United States in connection with the attack.

The Libyan national appeared in court in the US capital on Monday charged in connection with the bombing which downed Pan Am flight 103 over Lockerbie in 1988, killing 270 people including 11 people on the ground.

Speaking to The Herald on Sunday Mr MacAskill, a former SNP justice secretary, said Ms Bain should find out what was being made on bringing Abdullah Senussi to court.

It was reported in 2015 that Scottish police were trying to interview Senussi, the brother-in-law and intelligence chief of former Libyan dictator Colonel Gaddafi.

"The interesting thing is why have they not got Senussi? Senussi is even more evil than Masud and was responsible for everything.

"Senussi was Gaddafi's spy master. He was the deputy leader and is understood to be in a jail in Libya. He's the main man," said Mr MacAskill, who is now an Alba Party MP.

"[Libya] have not offered him up. They have offered up Masud. But Masud is smaller beer."

Mr MacAskil pointed to the UK's authorities interrogation of Gaddafi's former foreign minister Moussa Koussa who defected to the west, arriving in the UK in March 2011 at the start of the civil war in Libya. He now lives in Qatar.

"I think the US and the UK through their secret services know what's going on and they should be telling us," he said.

"Britain and America know everything. I want the UK and US to be more open. The Lord Advocate could ask."

As justice secretary, Mr MacAskill released Abdelbaset Al-Megrahi on compassionate grounds in 2009 after he was convicted of the bombing in 2001. He had been diagnosed with terminal cancer and died in Tripoli in 2012.

A second suspect, Al Amin Khalifa Fhimah, stood trial with al-Megrahi but was acquitted.

It is not clear how Masud was apprehended by US officials.

In 2020, he was charged by the US Attorney General William Barr with being the third person involved in the terrorist attack.

At the time, he was said to be in Libyan custody and Mr Barr said US authorities would work “arm in arm” with their Scottish counterparts.

Mr Barr said: “Let there be no mistake, no amount of time or distance will stop the US and our Scottish partners from pursuing justice in this case.”

“The obvious way forward it seems to me is to resort to the United Nations and invite them to provide a court with appropriate facilities to try this man and hopefully to review all the evidence that was used against the unfortunate Megrahi.”

The BBC reported in 2015 that Scottish prosecutors wanted to interview Masud and Senussi after identifying both as suspects over the Lockerbie bombing.

At that time Senussi was reported to have been in prison in Libya awaiting execution after having been sentenced to death by firing squad.

Pan Am 103 flight was on its way from London to New York when it exploded above Lockerbie killing everyone on board and 11 people on the ground.

Both men were named as possible suspects in the bombing by an American TV documentary in 2015.

A Crown Office spokesman said at the time: "The Lord Advocate and the US Attorney General have recently agreed that there is a proper basis in law in Scotland and the United States to entitle Scottish and US investigators to treat two Libyans as suspects in the continuing investigation into the bombing of flight Pan Am 103 over Lockerbie.

"The Lord Advocate has today, therefore, issued an International Letter of Request to the Libyan attorney general in Tripoli which identifies the two Libyans as suspects in the bombing of flight Pan Am 103."

The Crown Office told The Herald on Sunday that there are currently no criminal proceedings in Scotland against Senussi and none have been issued to date.

Libya's Government of National Unity, the internationally recognized administration in Tripoli, had no comment on Masud's transfer to the United States.

However, its political rivals have accused it of illegally handing him over to Washington to curry its support in Libya's ongoing standoff over control of government.

In a statement in Holyrood last Tuesday, Ms Bain said Masud was on the original Scottish indictment but did not currently face criminal proceedings in Scotland.

"The suspect is an individual who featured on the original Scottish indictment, and investigations into his involvement have continued over the years. Scottish prosecutors and law enforcement stand ready to afford all possible co-operation to our US partners in accordance with the rule of law and will continue to pursue the investigation into the involvement of all those who were part of this terrorist attack," she told MSPs.

"The US authorities have confirmed that Mr Masud was transferred to US custody on a lawful basis, following upon US authorities making a formal extradition request for him from Libya to stand trial in the US in March 2021."

She added: "A joint investigation is being carried out, with American and Scottish prosecutors and law enforcement officers working together, as they have done for the past 34 years. There are no current criminal proceedings in Scotland against Mr Masud."