The New York Times has looked into it and decided it couldn't find any evidence Al Qaeda was involved in the 2012 attack on the US mission in Benghazi in which the US ambassador to Libya and three others were killed.
From Voice of America:
A leading U.S. newspaper says American intelligence efforts in Libya that fixated on al-Qaida likely contributed to the killing of the American ambassador to Libya in 2012.
The New York Times reported Saturday it could not find any evidence, after months of investigation, that al-Qaida or any other international terrorist groups had any role in the attack on the American consulate in Benghazi that killed Ambassador Christopher Stevens and three other Americans.
The newspaper said the "fixation" on al-Qaida possibly distracted intelligence experts from "more imminent threats," including local anti-Western militia leaders such as Ahmed Abu Khattala, and the angry reaction to an American-made video denigrating Islam.
Some Republican and Democrat lawmakers in the House dispute the conclusion, and suggest US intelligence has concluded otherwise. The renewed assertions about a low budget YouTube video have also been contradicted by top US officials on the ground in Libya, and remain a distraction to what happened.
Watch Reason TV's Three Reasons Benghazi Still Matters below: