The US Senate Foreign Relations Committee has scheduled a July 29 hearing into last year's release of a Libyan convicted for the 1988 bombing of an airliner over Lockerbie, Scotland, and related actions by BP. The committee said on Thursday it will ask officials of BP Plc to testify after the UK-based oil giant acknowledged that it had lobbied the British government in 2007 to agree to transfer Libyan intelligence officer Abdel Basset al-Megrahi to Tripoli. The company said it was concerned that his continued imprisonment in Scotland could negatively affect an offshore oil drilling deal with Libya. “BP told the UK government that we were concerned about the slow progress that was being made in concluding a prisoner transfer agreement with Libya,” BP said in a statement. Senate Foreign Relations Committee Chairman John Kerry, who had opposed Megrahi's release, said “details that have emerged in recent days in the press have raised new concerns.” Britain's ambassador to Washington sent a letter to Kerry on Thursday “to explain the facts” surrounding the circumstances of Megrahi's release. “Under Scottish law, Megrahi was entitled to be considered for release on compassionate grounds. Whilst we disagreed with the decision to release him, we have to respect the independence of the process,” Sir Nigel Sheinwald said in the letter. “I am troubled by the claims made in the press that Megrahi was released because of an oil deal involving BP, and that the medical evidence supporting his release was paid for by the Libyan government. Both of these allegations are untrue,” Sheinwald added. Sheinwald said he hoped his letter would help to set the record straight and correct inaccuracies that he said were harmful to the United Kingdom. Megrahi, the only person convicted in the bombing of Pan Am flight 103 over Lockerbie that killed 270 people, was released on medical grounds, which have come under question. The Scottish government, which has broad legal powers under the UK political system, had been advised that he was likely to die within three months of advanced prostate cancer. But nearly a year later, he is still alive and living in Tripoli, the Libyan capital. British Prime Minister David Cameron and U.S. President Barack Obama are to meet on Tuesday at the White House, but it was not known whether BP's role in the prisoner release would be raised. The Senate panel said it will ask “government experts” to testify at the hearing, but did not release details on witnesses it plans to invite. Secretary of State Hillary Clinton said she would look into a request by several senators that her agency investigate.