The head of the National Counterterrorism Center appeared before Congress Wednesday to update lawmakers on the investigation into last week’s deadly attack on the U.S. consulate in Benghazi. Matthew Olsen said although the perpetrators remain unknown, it’s clear the assault was a premeditated “terrorist attack.”

Matthew Olsen: “Certainly on that particular question I would say, yes, they were killed in the course of a terrorist attack on our embassy. A number of different elements appear to have been involved in the attack, including individuals connected to militant groups that are prevalent in eastern Libya, particularly in the Benghazi area. As well, we are looking at indications that individuals involved in the attack may have had connections to al-Qaeda or al-Qaeda’s affiliates, in particular al-Qaeda in the Islamic Maghreb.”