Last month's attack killed ambassador Christ Stevens and three other Americans. It is now believed to have been carried out by al Qaeda-linked militants.
This week, a five-member accountability review board appointed by Secretary of State Hillary Rodham Clinton, will begin looking at whether security at the consulate was adequate. The board will also look into whether proper procedures were followed before, during and after the attack.
Republican lawmakers claim security at the consulate was inadequate. Two House leaders have asserted that the Obama administration denied repeated requests from U.S. diplomats in Libya to enhance security at the mission.
Clinton promised a transparent-as-possible process, although she stressed it will take time. Facing Republicans in Congress eager for full details of any possible negligence before the Nov. 6 presidential election, Clinton pledged that the State Department would share information as soon as possible.
At the same time, she cautioned that the Accountability Review Board led by former chairman of the Joint Chiefs of Staff, retired Adm. Mike Mullen, should not be rushed to judgment.
Meantime, the FBI confirmed on Thursday that a team of agents arrived in Benghazi on Wednesday to investigate the consulate attack. FBI spokeswoman Kathy Wright said the agents were there just one day. She would not say where the team is headed. Law enforcement officials had said earlier that the FBI had been staying away from the Libyan city for security reasons.
The Associated Press contributed to this report.