'Credible' 9/11 Threat Hasn't Expired: Officials Sept. 11 may have passed, but terrorist threat hasn't By Kate Seamons, Newser Staff Posted Sep 13, 2011 11:02 AM CDT 3 comments Comments Ayman al-Zawahri might be behind the unconfirmed plot. (AP Photo/IntelCenter) (Newser) – Three words you don't want to hear in the same sentence: credible, threat, unresolved. Unfortunately, that's the word out of the National Counterterrorism Center. USA Today reports that NCC director Matthew Olsen, along with Janet Napolitano and Robert Mueller, today told the Senate Homeland Security Committee that while Sept. 11 may have come and gone, the specific threat made to the US around the anniversary remains a concern. "We are not prepared to say it is resolved,'' says Olsen. Since last week, the government has been working to confirm that operatives were traveling to or already inside the US, and planned to detonate a car bomb in either New York or Washington, possibly on the orders of al-Qaeda leader Ayman al-Zawahri. Mueller notes that the government has conducted hundreds of interviews and is pursuing leads related to the unconfirmed threat, reports the AP.