A doctor who examined the Lockerbie bomber says he could not have faked his illness.
Leading oncologist Professor Karol Sikora examined Abdelbaset al-Megrahi, who has terminal prostate cancer, in prison and estimated he had about three months to live.
Last August, the Libyan was released from jail on compassionate grounds.
Megrahi is still alive, although there are no current reports on his health.
His release provoked fury in the US, where politicians are looking into claims that the release was linked to oil deals with Libya - a claim that has been denied.
Megrahi was jailed in 2001 for the 1988 bombing over the Scottish town of Lockerbie, which claimed 270 lives.
"I am surprised he is still alive," said Professor Sikora, who was asked by the Libyans to give a medical opinion on Megrahi's health prior to his release.
He said he did not believe he and other experts had been fooled.
"You take into account the type of cancer he had, and the X-ray evidence that it had spread. The blood test for PSA (prostate specific antigen) was rising - everything pointed towards the fact that he had end-stage disease."
Seeds of doubt
Former prison doctor and writer Theodore Dalrymple agreed that it would be impossible for Megrahi to fake the severity of his disease.
"There is a difficulty of knowing prognosis, with medicine not being an exact science.
"You can't say, except in very rare cases, that somebody is going to die on the 14th of April next.
"And just because someone has certain symptoms, it is not possible to say someone will die within weeks.
"The reason you are suspicious is because you suspect prisoners might have been pulling the wool over your eyes.
"With something like dementia it is possible, but I don't think is is possible to act respiratory failure or cancer."
Section 3 of the Prisoners and Criminal Proceedings (Scotland) Act 1993 gives Scottish ministers the power to release prisoners on licence on medical grounds.
In Scotland, only 26 prisoners have been released in the last decade, with seven requests denied.
Eleven of those died within days of release; only two survived more than six months - one for 16 months - and of these only Megrahi, who was one of the last to be released, is still alive.
The release of Megrahi is still causing controversy, with the US Senate's Foreign Relations Committee currently investigating the circumstances behind it.
It is led by Senator Robert Menendez, who is asking for the release of all relevant medical documents.
A report in the Wall Street Journal suggests the specialists who had been treating Megrahi did not sign up to the three month prognosis.
But a spokesman for the Scottish government told the paper that Dr Andrew Fraser, head of health and care for the Scottish Prison Service who made the decision to release Megrahi on compassionate grounds, had drawn on clinical advice from a number of specialists - not including Professor Sikora - before backing the three-month prognosis.