As we noted here 12 days ago, the Senate Foreign Relations Committee had scheduled a hearing this week to look into the circumstances surrounding the release of convicted Lockerbie bomber Abdel Basset Mohamed al-Megrahi.

An angry Senator Robert Menendez announced this afternoon that the hearing has been postponed, because the major witnesses he wanted to testify wouldn't agree to cooperate. Those include outgoing BP chief Tony Hayward; Kenny MacAskill, the Scottish Justice Secretary who made the decision last year to release al-Megrahi; the Scottish doctor whose diagnosis prompted the Libyan's release on medical grounds; and former British Justice Secretary Jack Straw.

Menendez, a Democrat from New Jersey, from where many of the bombed Pan Am flight's victims came, vowed not to be deterred, saying the committee would instead open a lengthy investigation of the circumstances surrounding Megrahi's release.

"We are at place where no witness of consequence has the courage to step forward and clear the air - they would prefer to sweep this under the rug," Menendez said. "We also have not had the time to extract key documents that could help illuminate the issue. As such, we are shifting our efforts to a longer-term, multi-dimensional inquiry into the release of al-Megrahi."

Reports of BP's role in British-Libyan negotiations over a prisoner transfer agreement have threatened to further complicate the U.S.-U.K. "special relationship," already tense in some quarters because of BP's Gulf oil spill.

But while the British oil giant has acknowledged lobbying on behalf of completing the prisoner transfer deal with Libya, where it hoped to conduct offshore deep-water drilling, no evidence has emerged of direct BP involvement in al-Megrahi's case. And al-Megrahi was freed on humanitarian grounds (a move the new British prime minister, David Cameron, said he opposed), not under the prisoner transfer deal.

Menendez excoriated the witnesses for refusing to appear. "It is utterly disappointing that none of these key witnesses will cooperate with our request to answer questions before the Foreign Relations Committee," he said. "They have stonewalled. Each side has claimed innocence. ... Each side has blamed the other. .. It is a game of diplomatic tennis that is worthy of Wimbledon."

"In the case of BP, it is hard to imagine that a company on such thin ice with the American public after devastating our Gulf Coast would not fully cooperate in getting to the bottom of the release of a terrorist who murdered 189 Americans."