Amid BP’s problems in the gulf, the energy giant is also facing accusations it played a role in winning the release of the man convicted of the 1988 Lockerbie bombing.
Abdel Baset Al-Megrahi, who has terminal prostate cancer, was freed on compassionate grounds in August 2009 after serving eight years.
Four US senators are now asking the US state department to investigate whether BP lobbied for his release while attempting to finalise an oil deal with Libya two years earlier.
Senator Robert Menendez said: “If BP is found to have gained access to Libyan oil reserves by using a mass murderer as a bargaining chip, then make no mistake – any money it makes off that oil is blood money, pure and simple.”
The bombing of Pan Am flight 103 killed 270 people, mostly American.
BP has denied specifically lobbying for al-Megrahi’s release, saying it was a matter for the UK and Libyan governments.