Eddie Barnes: As the anniversary of the Lockerbie bomber's release looms are we any closer to solving the riddle?

That day, images had been beamed around the world of Abdelbaset Ali Mohmed al-Megrahi, attending a pro-Gaddafi event in Libya, as the regime used his presence on state TV as propaganda to boost their flagging cause. In Washington, one of the journalists piped up: "Do you have a response to the appearance today of the perpetually ill, always-on-his-last-days Lockerbie bomber at a rally in Tripoli?" Spokesman Mark Toner, dead-bat, replied: "I'm not going to comment."

For relatives of the dead, though, it is no laughing matter. Frank Duggan, the president of the Victims of Pan Am 103 group, is well aware that come 20 August of this year another inglorious anniversary in the Lockerbie tragedy will pass; the second year since Megrahi was released from Greenock Jail and returned home, accompanied by Colonel Gaddafi's son Saif, to a hero's welcome in Tripoli. Were the group planning anything to mark the two years? Duggan sighs. "No. It is something that is so upsetting to so many people that the last thing we want to do is mark it in any way. There is nothing that anyone can do. Our government did everything they could to keep him from being released. But there it is."

The outrage felt by many Americans over Megrahi's continuing liberty remains, but it appears a certain resignation has now set in.

Megrahi's appearance last week - the first time he has been pictured in public for well over a year - was badly timed for the Scottish ministers who released him in 2009, and justice secretary Kenny MacAskill in particular. In the fuzzy image shown, Megrahi looked frail and appeared to be seated in a wheelchair. But then - as the US journalist noted last week - he has looked frail now for quite some time. And as the days tick by since he walked up the steps to his waiting private jet at Glasgow airport two summers ago, so the questions only become more pressing.

The anniversary coincides with the historic events happening in Libya which, in a matter of weeks, may see the Gaddafi regime fall, and with it, a thousand secrets exposed. Is this the summer when we finally get the answers over the Megrahi mystery, not just over how he ever came to be released, but over his guilt in the first place?

Megrahi's release two years ago, on compassionate grounds, was made on the basis that it was "reasonable" to conclude he had only three months to live.The verdict was given by Dr Andrew Fraser, the head of health at the Scottish Prison Service, whose advice to MacAskill was the key piece of evidence the minister required to be able to sanction compassionate release. The subsequent two years since that verdict haven't just exposed its shortcomings, they have also seen mounting questions over exactly how that "reasonable" conclusion was made.

Within weeks of Megrahi's return, papers released by the Scottish Government showed that four specialists who examined Megrahi "were not willing to say" whether or not he would survive more or less than three months. One, Dr Zac Latif, a consultant urologist, was later quoted as saying that he wasn't asked his opinion about Megrahi's prognosis, saying he was always "reluctant" to make any prediction on prostate cancer, the disease from which Megrahi suffers. Dr Fraser's conclusion appeared to have been based on the opinion of another doctor - believed to be a GP - who had concluded his "clinical condition has declined significantly over the last week".

However, another of the cancer specialists, Dr Grahame Howard, said that while he was "not surprised" that Megrahi had survived longer than three months, Dr Fraser's conclusions were "a fair reflection of the specialist advice available at that time". The medical report submitted to the justice secretary, recommending release, was also backed by the Parole Board for Scotland and the prison governor. "In every regard, due and proper process was followed at every stage," a spokesman for the Scottish Government insists.

The fact appears to be that Megrahi was a very sick man at the time his decision was being made who, upon returning to Libya, has got better, or at least stabilised. The thing is, say other experts, this was entirely predictable. Professor Roger Kirby, a leading prostate surgeon and founder of the Prostate Centre, said last week: "It was always foolhardy to put a three-month prognosis on his survival, because advances in treatment, such as new chemotherapy and immunotherapy techniques that he is likely to be receiving, could keep him alive for a while yet, maybe even several more years. What used to be a hopeless situation for patients at advanced stages of prostate cancer is now more favourable."

The reasoning behind that release has now become a source of lengthy debate, with the oil deals struck between Libya and BP and motives of the UK Government under intense scrutiny. In the case of Scottish ministers, Alex Salmond's case now is that the decision was made "in good faith". Another way of putting this, say relatives of those who died, is that "the Scots got duped".

The situation has now reached farcical levels. East Renfrewshire Council, in whose area Megrahi's family were living when he was in Greenock jail, confirmed last week that they continue to contact him every month and still receive a medical report from his doctors, as they are in charge of his release licence.Bizarrely, that licence - and the Prison Service's guidance on compassionate release - states that Megrahi could be told to get back to jail; the guidance notes that "if a prisoner who has been granted compassionate release because of a terminal illness makes an unexpected recovery, consideration would be given to revocation of the licence and the return to custody".

However, as everyone knows, the Scottish authorities are utterly powerless to do so, given that Megrahi is in Libya - and also now under the care of a regime which Britain no longer recognises anyway. Scottish Labour leader Iain Gray says: "Labour said at the time that the licence conditions would be utterly unenforceable, and that was before the war in Libya. However strong the case for revoking the licence, there is no practical solution."

Nonetheless, say opposition parties, while the situation may be impossible to resolve, the SNP Government should release all the medical reports concerning Megrahi anyway. Ever since his release, both the medical reports which led to Dr Fraser's report and the monthly reports from Tripoli have been kept secret because it would break Megrahi's right to privacy (a view supported by Scotland's Information Commissioner).

But, say opponents, the rights of Megrahi to have his medical records kept secret are massively outweighed by the rights of the public and the families of those who died to know what's going on.

John Lamont, justice spokesman for the Scottish Conservatives, said last night: "Every month that passes, people get more suspicious about the reason the Scottish Government continues to refuse to release the medical advice. The recent pictures haven't helped and we should also see sight of the ongoing medical assessments of his health in Tripoli. Nearly two years after his release, the onus is now on the Scottish Government to come clean."

Under pressure once again, MacAskill last week repeated the now familiar words he had used two years ago when he told the world that the man found guilty of Britain's worst terrorist atrocity could pack his bags and go home. Megrahi was suffering from a terminal illness; his fate was in the hands of a higher power; the Scottish Government had acted in good faith - and not with reference to any "deals in the desert".

And while MacAskill will find himself under greater pressure, it may be that the focus moves away from the decision to set him free to the decision to convict him in the first place. Last week, Salmond repeated his pledge to publish a confidential report, compiled by the Scottish Criminal Cases Review Commission, which sets out its reasons for sending Megrahi's conviction back to the Court of Appeal in Edinburgh.If published, the report, which was locked away after Megrahi dropped his appeal, is likely to put fresh scrutiny on his involvement in the bombing.

At the same time, further light may be shed by Musa Kusa, Colonel Gaddafi's former foreign minister, who defected to the UK in April and who was questioned by the Crown Office and Dumfries and Galloway police soon after about his knowledge of the bombing. The Crown Office refused to say yesterday whether Kusa had been interviewed again, although it is understood he remains out of the country, possibly in Qatar.

Inquiries by Scottish prosecutors remain "ongoing". The Crown Office is examining new evidence to establish whether it can retry Al-Amin Khalifa Fhimah, Megrahi's co-accused who was found not guilty at the Camp Zeist trial in 2001. Prosecutors are re-examining evidence to see whether it is strong enough to invoke the new double jeopardy law, which allows prosecutors to try someone twice for the same offence.

Meanwhile, US Senators are hoping to use the Libyan revolution to spirit Megrahi back out of Libya to the US. Having watched Megrahi on the TV, Democrat Senator Robert Menendez said last week: "I will continue to work to ensure that any new government in Libya co-operates with efforts to extradite Mr al-Megrahi to the United States to pay for his crimes."

Menendez and veteran fellow Democrat Frank Lautenberg have written to Hillary Clinton urging her to act. As we report today, the Justice for Megrahi group - which insists he is innocent - are calling on the SNP Government to offer Megrahi the option of returning to Scotland if he wishes to avoid what they describe as the threat of his "rendition" to the US. Robert Forrester, the secretary of the group, says: "It is now of vital importance that the Scottish authorities at least offer Mr al-Megrahi an open door through which to escape his current circumstances if he wishes to do so, not least because so many profound doubts exist over his 2001 conviction."

Such a move would be seen as the ultimate betrayal by families in the US, however, many of whom - such as Duggan - believe 100 per cent in Megrahi's guilt, and view those who consider him innocent as hopelessly naive. As he approaches a second anniversary which none of them ever dreamed of experiencing, Duggan's view of matters is understandably cynical. "There is no credible medical evidence. So the conclusion is that the man was let go for what were diplomatic, commercial and political reasons," he says. It may also be a case that a very sick man is clinging on to life, now that he has something to live for. If he continues to do so, he may finally see the riddle of his life finally brought to light.