And yet he lied, lied, and lied some more about it for about two weeks. The e-mail trail shows they knew the cause within two hours after the attacks began:
The emails, obtained by Reuters from government sources not connected with U.S. spy agencies or the State Department and who requested anonymity, specifically mention that the Libyan group called Ansar al-Sharia had asserted responsibility for the attacks.
The brief emails also show how U.S. diplomats described the attack, even as it was still under way, to Washington.
U.S. Ambassador Christopher Stevens and three other Americans were killed in the Benghazi assault, which President Barack Obama and other U.S. officials ultimately acknowledged was a "terrorist" attack carried out by militants with suspected links to al Qaeda affiliates or sympathizers.
Administration spokesmen, including White House spokesman Jay Carney, citing an unclassified assessment prepared by the CIA, maintained for days that the attacks likely were a spontaneous protest against an anti-Muslim film.
While officials did mention the possible involvement of "extremists," they did not lay blame on any specific militant groups or possible links to al Qaeda or its affiliates until intelligence officials publicly alleged that on September 28.
There were indications that extremists with possible al Qaeda connections were involved, but also evidence that the attacks could have erupted spontaneously, they said, adding that government experts wanted to be cautious about pointing fingers prematurely.
U.S. intelligence officials have emphasized since shortly after the attack that early intelligence reporting about the attack was mixed.
Spokesmen for the White House and State Department had no immediate response to requests for comments on the emails.
I guess Chris Matthews doesn't get his news from Reuters.