A man whose daughter was among 270 people killed in the Lockerbie atrocity has described the convicted bomber's death as a "very sad event".
Dr Jim Swire did not believe Abdelbaset al Megrahi was to blame for the 1988 bombing - and said his conviction had been an "obstruction" in the search for the truth about the attack.
Dr Swire, whose daughter Flora died, told Sky News: "It's a very sad event. I met him in Tripoli in December last year, when he was very sick and in a lot of pain.
"But he still wanted to talk to me about how information which he and his defence team have accumulated could be passed to me after his death."
Megrahi , 60, was the only man ever convicted over the terrorist attack, despite claims that he could not have worked alone, and the continuing belief by some that he was innocent and others were involved.
The former Libyan intelligence officer, who suffered from prostate cancer, died almost three years after being released from a Scottish prison on compassionate grounds because doctors said he had only three months to live.
He was greeted like a hero by the Gaddafi regime on his return to Libya in 2009, having served eight years of a 27-year sentence after being convicted by a Scottish court in 2001.
The scenes sparked fury from American families, who were among the most outspoken critics of the decision to release him.
All 259 people on the airliner died and 11 others on the ground in the Dumfries and Galloway town were killed in Britain's biggest terrorist atrocity.
Dr Swire said of Megrahi: "Right up to the end he was determined - for his family's sake, he knew it was too late for him, but for his family's sake - how the verdict against him should be overturned.
"And also he wanted that for the sake of those relatives who had come to the conclusion after studying the evidence that he wasn't guilty, and I think that's going to happen."
David Ben-Ayreah, a spokesman for the victims of Lockerbie families, said: "I was told seven days ago by very good sources in Tripoli that he was slipping in and out of quite deep comas, that the secondary tumours had affected his abdomen and lower chest, and that he had had three blood transfusions.
"His death is to be deeply regretted. As someone who attended the trial I have never taken the view that Megrahi was guilty.
"Megrahi is the 271st victim of Lockerbie."
However, Bert Ammerman, the brother of a Lockerbie victim, said: "I'm pleased with the death of Megrahi. I was most angered when (Megrahi was released) on ridiculous grounds of compassion.
"I do agree Megrahi's death does minimal for finding out the truth... I do believe that more people than Megrahi were involved."
Prime Minister David Cameron , who is in Chicago attending a Nato summit, gave his reaction to the death.
"I have always been clear that he should never have been released from prison," he said.
"But today is a day to remember the 270 people who lost their lives in what was an appalling terrorist act and our thoughts should be with them and their families and the suffering that they've had."
The former British ambassador to Libya , Oliver Miles, told Sky News his death would not automatically trigger any inquiry into the early release of Megrahi.
Sky's political editor Adam Boulton said there was "no doubt that this news will have a very significant impact".
"The American government always opposed the release of Megrahi on compassionate grounds back in 2009 - as indeed did David Cameron, then the leader of the Conservative opposition," he said.
"So the death of this convicted man... will I think help in drawing a line under that period where relations with Colonel Gaddafi's Libya were in active play, where there was give and take on both sides."
Sky's Scotland correspondent James Matthews said investigations were continuing and British police are set to be sent to Libya in the near future to attempt to gather more information.
Megrahi had rarely been seen since his return to Tripoli, but he was spotted on Libyan television at what appeared to be a pro-government rally in July 2011.
UK Foreign Secretary William Hague said at the time that the public appearance confirmed that a "great mistake" was made in releasing him from jail.
In 2010, the Guardian reported that leaked US diplomatic cables showed the former Libyan leader Colonel Gaddafi had warned of "repercussions" if Megrahi was to die in prison and threatened to cut trade with Britain.
Prior to Megrahi's death, reports suggested his prostate cancer had spread to his neck.
Others said he had been kept alive with cancer drugs unavailable in the UK.
Mr Cameron has come under pressure from US senators for an inquiry into the decision to free the bomber. Scottish ministers have always insisted their decision was made in good faith .