Updated

A senior Scottish prosecutor and the head of the FBI have traveled to Libya to discuss the investigation into the 1988 Pan Am bombing that killed hundreds over Lockerbie.

Scotland's public prosecution office said in a statement Wednesday that Scotland's most senior legal officer Frank Mulholland and FBI director Robert Mueller traveled to Tripoli to meet Libyan prime minister Abdurahim el-Keib to discuss the case.

It says the meeting took place on April 25 but was not publicized at the time for security reasons.

Only one man, Abdel Baset al-Megrahi, has been convicted of the bombing. He was freed from a Scottish jail on compassionate grounds in August 2009, suffering from cancer. The Libyan authorities have said they will cooperate in investigations on the bombing.