A review of US government records found no information about BP attempting to influence the release of the Lockerbie bomber, a committee hearing in America was told.
Members of the United States Senate Foreign Relations Committee are investigating the circumstances of the release including whether it was linked to an oil deal - a suggestion strongly denied by all parties involved.
Yesterday, Nancy McEldowney, a principal deputy assistant secretary in the State Department, said the department had "not identified any materials, beyond publicly available statements and correspondence, concerning attempts by BP or other companies to influence matters" related to Abdelbaset Ali Mohmed al-Megrahi's release.
The Libyan is the only person to be convicted of the 1988 bombing of Pan Am Flight 103 over Scotland, in which 270 people died - most of them Americans.
Scottish Justice Secretary Kenny MacAskill released the prostate cancer sufferer on compassionate grounds 13 months ago after he was given three months to live, but he remains alive today.
The decision sparked fury in America and was condemned by President Barack Obama's administration.
The Foreign Relations committee was told that Ms McEldowney had noted that in 1998 the US and Britain wrote a letter to the secretary general of the United Nations, outlining an agreement for Megrahi and another suspect to be tried before a Scottish court established in the Netherlands.
The letter stated: "If found guilty, the two accused will serve their sentence in the United Kingdom."
She said that back then, the US sought binding assurances that would happen, but the British countered that they could not legally bind the hands of future governments.
"They nonetheless assured us of their political commitment that, if convicted, al-Megrahi would remain in Scotland until the completion of his sentence," Ms McEldowney said.
The committee hearing was postponed earlier this year after key witnesses including former justice secretary Jack Straw, Mr MacAskill and Scotland's First Minister Alex Salmond turned down requests to attend.
At yesterday's session, Bruce Swartz, deputy assistant attorney general, said that both the Justice and State Departments stressed that Megrahi serve his full sentence in Scotland from the very beginning.
"This was one of the earliest issues raised by the United States in connection with the negotiations for a trial before a Scottish court in the Netherlands, and the United States continued to raise it following Megrahi's conviction and incarceration," he said in prepared testimony.
A Scottish Government spokesman said last night: "With the US State Department saying that there is no evidence whatever that BP played a role in the release of al-Megrahi, the entire basis of the Senate committee hearing has fallen away - we have been telling them that in letter after letter, and in a meeting, for many months.
"The Scottish Government has published everything we can - except where permission was withheld by the US and UK administrations - and all of the evidence demonstrates that the Justice Secretary's decisions to reject the prisoner transfer application and grant compassionate release were taken on judicial grounds alone - and not political, economic, diplomatic or any other factors.
"Scottish ministers and officials are accountable to the Scottish Parliament, and the Parliament's Justice Committee held a full inquiry into this issue - which it decided not to re-open."
The spokesman said Scottish ministers had also given "substantial help" to the Senate committee and the First Minister had written to the Senators involved in the committee.
The spokesman also "totally rejected" claims a Scottish Government official said, during discussions with committee representatives earlier this month, that the three-month prognosis for Megrahi was signed off by a primary care physician.
The spokesman said it was also a "matter of public record that Megrahi was not on chemotherapy treatment in Scotland at any point" and claims Megrahi was receiving the treatment before his release were not correct.
The Scottish Government wrote to the Senate committee yesterday evening when they became aware of the "misinformation".
Earlier this month Scottish Government officials met representatives of the US Senate committee in Scotland.
A spokesman for the SNP administration said it was an "amicable" meeting.
"We believe that it was a helpful exchange," the spokesman added earlier this month.Reuse content