Libyan officials say the head of the FBI is in Tripoli for talks on the investigation into last year's killing of the U.S. ambassador and three other Americans in the eastern city of Benghazi.
The officials say FBI director Robert Mueller arrived Thursday and is to meet with senior Libyan officials, including the prime minister, justice minister and intelligence chief. They spoke on condition of anonymity because of the sensitive nature of the visit.
Ambassador Chris Stevens and the other Americans were killed in Benghazi last September in an attack that Washington suspects was carried out by Al Qaeda-linked militants.
There has been little news of progress so far in the investigation, and U.S. officials have complained about poor cooperation with the governments of the region in the case.