A police officer stands guard in New York's Times Square as the ABC news ticker displays news of an al-Qaida terror threat, Friday, Sept. 9, 2011. Just days before the 10th anniversary of the Sept. 11 attacks, U.S. counterterrorism officials are chasing a credible but unconfirmed al-Qaida threat to use a car bomb on bridges or tunnels in New York City or Washington. It is the first
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