US Ambassador Christopher Stevens

Then-U.S. envoy J. Christopher Stevens attends meetings at the Tibesty Hotel in Benghazi, Libya. (April 2011 file photo)

J. Christopher Stevens, newly appointed U.S. ambassador to Libya, shakes hands with Libyan National Transitional Council (NTC) chairman Mustafa Abdel Jalil (R) after presenting his credentials during a meeting in Tripoli, June 7, 2012.

Then-U.S. envoy Christopher Stevens speaks to local media before attending meetings at the Tibesty Hotel where an African Union delegation was meeting with opposition leaders in Benghazi, Libya. (April 2011 file photo)

In this photo posted on the U.S. Embassy Tripoli Facebook page, Christopher Stevens poses with a shop owner in Tripoli, Libya, August 12, 2012.

دوستداران نلسون ماندلا در گرامیداشت یاد او شمع روشن کردند. پاریس، ۵ دسامبر

Christopher Stevens (R), Britain's diplomatic representative Christopher Prentice (L) and deputy chairman of the TNC Abdul Hafiz Ghoqa (C) attend a memorial service for slain photojournalists Tim Hetherington an Chris Hondros in Benghazi, April 2011.

U.S. Ambassador-at-Large Stephen Rapp with Christopher Stevens (C), after a meeting with Libyan Justice Minister Ali Ashour discussing cooperation between the two countries on issues of human rights, in Tripoli June 27, 2012.