10/24/2012 05:42 pm ET Updated Dec 24, 2012

Ali Al Harzi,Tunisia Man, Arrested For Role In Attack On U.S. Consulate In Libya

WASHINGTON, Oct 24 (Reuters) - A suspected Islamic militant under arrest in Tunisia is being investigated by the United States in connection wi th the Sept. 11 attacks on U.S. diplomatic facilities in Benghazi, Libya, U.S. government sources said.

The suspect , identified earlier this week by the Daily Beast website as Ali Ani al Harzi, was one of two Tunisians detained by authorities in Turkey early in October.

News reports at the time of their detention said that the two men were stopped at an Istanbul airport as they tried to enter the country using false passports. The Turkish Embassy in Washington declined to comment.

U.S. government sources have told Reuters that only one of the men, now understood to be al Harzi, was under investigation in connection with the Benghazi attacks, in which Christopher Stevens, the U.S. ambassador to Libya, and three other American officials were killed.

One of the sources said that Turkish authorities subsequently sent al Harzi back to Tunisia.

An official at the Tunisian Ministry of Justice confirmed a man had been arrested but denied he was linked to the killing of Stevens.

"The arrested person was deported by Turkey last month, but he has nothing to do with the killing of the U.S. ambassador," he told Reuters without giving more details.

Another U.S. government source said U.S. investigators believed that al Harzi "had something to do with (the Benghazi violence) for sure."

The sources said, however, that at this point al Harzi was not being investigated as a leader or organizer of the Benghazi attacks but rather as a possible participant.

The Daily Beast reported that shortly after the Benghazi attacks began, al Harzi posted an update on an unspecified social media site about the fighting. The Da ily Beast s a id this was one of the first clues tha t U.S . intelligence agencies acquired as to who might be behind the violence.

The Daily Beast said al Harzi was on his way to Syria when he was detained in Turkey a t the behest of U.S. authorities, and that he was affiliated with a militant group in North Africa. Neither the website nor U.S. government sources identified the group with which he allegedly is associated.