Najibullah Zazi and the Missing 40 Minutes

In the tense final days before the FBI arrested Afghan-American Najibullah Zazi on terror-conspiracy charges, the Feds had a major scare: NEWSWEEK has learned that Zazi managed to shake off the posse of Joint Terrorism Task Force investigators who were tailing him and disappeared for anywhere between 40 and 90 minutes. Now the Feds worry that during the time he was missing, Zazi could have ordered associates to get rid of a suspected cache of bombmaking materials that they believe the suspects had amassed.

Two knowledgeable sources, who asked for anonymity when speaking about an ongoing inquiry, say that on Sept. 10, investigators pulled over Zazi for what they claimed was a random drug stop on the George Washington Bridge to New York City. It's unclear why they stopped him, or what, if anything, Zazi told them. But he may have grown suspicious, they say, because the next day he slipped the surveillance team during a ride on the New York subway. As one official put it: the investigators "freaked out," in part because it was the anniversary of 9/11 and they feared Zazi's plan might have been to launch his attack on the New York transit system that day.

The surveillance team eventually found Zazi. But investigators now want to know if, during the missing minutes, he somehow arranged for evidence of the alleged plot to be hidden or destroyed.

How did the Feds lose track of Zazi? Some investigators believe they may have inadvertently tipped their hand when they stopped him on the bridge the day before. Others say the surveillance team may have stuck out on the subway, making an already wary Zazi realize he was being tailed. There might be a more mundane explanation: one source close to the case says that, even though Zazi's "escape" was dramatic given the timing, it isn't all that unusual for law enforcement to lose track of a suspect temporarily, especially when cops are trying to blend in with the crowd to avoid being spotted.

Investigators say now that they have unraveled the alleged plot and captured Zazi, they have turned their attention to finding whatever bombmaking materials he may have hidden. That, they say, could take weeks or months—if they ever turn up. Investigators are hoping that the families of Zazi's presumed associates will pressure them to tell all to the Feds. A spokesman for the FBI had no comment, and a lawyer for Zazi, who has pleaded not guilty, could not be reached.