By Paul Cruickshank, Tim Lister, Nic Robertson and Fran Townsend
Several Yemeni men belonging to al Qaeda took part in the terrorist attack on the U.S. diplomatic compound in Benghazi last September, according to several sources who have spoken with CNN.
One senior U.S. law enforcement official told CNN that "three or four members of al Qaeda in the Arabian Peninsula," or AQAP, took part in the attack.
Another source briefed on the Benghazi investigation said Western intelligence services suspect the men may have been sent by the group specifically to carry out the attack. But it's not been ruled out that they were already in the city and participated as the opportunity arose.
The attack on the compound and subsequently on a "safe-house" to which Americans had been evacuated left four U.S. citizens dead, including the ambassador to Libya, Chris Stevens.
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