The UN Observer to the Lockerbie proceedings Dr Hans Kochler has issued a statement calling on US Senators to initiate a "meaningful" inquiry to deal with all aspects of Mr. Abdelbaset Ali Mohmed al-Megrahi's release".

In his statement Kochler also says the inquiry should address why Kenny MacAskill made "the unprecedented step to visit the Lockerbie convict in Scotland's Greenock prison and what exactly he discussed with him in private."

In his statement, Kochler refers to Megrahi as the Lockerbie "convict" throughout, rather than the more commonly used term "bomber".

"It is to be recalled that Mr. al-Megrahi withdrew his appeal on 12 August 2009, a few days after his meeting with the Justice Secretary (5 August), and, again a few days later (20 August), he was repatriated to Libya. It is also to be recalled that, under Scots law, "compassionate release" does not require the termination of trial or appeal proceedings," Kochler says.

"Only a release under the provisions of the Prisoner Transfer Agreement between the UK and Libya (that was initiated by then Prime Minister Tony Blair) would have required the termination of proceedings. The Scottish Justice Secretary deliberately chose not to make use of this option.

"A meaningful investigation should find out the real motives behind the decision of the Scottish Justice Secretary. In view of the unprecedented private meeting between a Secretary for Justice and a person convicted of mass murder (a conviction which, according to his own statements, Scotland's Justice Secretary does not question in any way), it is entirely appropriate to ask whether the decisive motive might have been the termination of proceedings so that the role of the Scottish, UK and US administrations in the handling of the Lockerbie case would never be fully scrutinized in a court of law.

"In view of the British Foreign Secretary's decision, in February 2008, to withhold supposedly secret evidence from the Defence, claiming "Public Interest Immunity" (PII), questions as to considerations of raison d'état (of the United Kingdom and, possibly, the United States) are not far-fetched.

"The families of the victims deserve better; and the rule of law requires more. The full truth of the Lockerbie tragedy must be known; the possible role of BP in the release of the only person convicted is only one of many aspects that would have to be investigated."

Kochler is one of a number of signatories to a petition calling on the UN to initiate a wide ranging inquiry into the Lockerbie affair, alongside Noam Chomsky, Archbishop Desmond Tutu, Tam Dalyell, Professor Robert Black and Dr Jim Swire.

Kochler's statement can be read in full, here.