Port Authority police were told to stop and search would-be subway bomber Najibullah Zazi's car last September as he drove up to the George Washington Bridge—but waved him across without finding two pounds of explosives hidden inside.
The failure to uncover the explosives after an alert about Mr. Zazi from the Federal Bureau of Investigation has been widely discussed among police but never publicly disclosed. It stoked longstanding tensions between the Port Authority Police and the New York Police Department, which are more pronounced since the 9/11 attacks. The Port Authority is tasked with protecting the bridges, tunnels and major airports between New York and New Jersey.
The Zazi case is especially sensitive for New York police, who privately argue that letting Mr. Zazi continue into the city was a potentially catastrophic gaffe by the Port Authority Police. Several NYPD detectives were accused of short-circuiting the case by talking to a Queens-based imam who worked as an NYPD informant. The imam was accused of alerting Mr. Zazi that police were on to him.
Ron Kuby, the attorney representing Imam Ahmad Wais Afzali, said evidence in his client's case suggests Mr. Zazi was tipped off by the staged FBI/Port Authority Police drug checkpoint before he ever spoke to the imam.
"Either the Port Authority [Police] found the explosives and were under orders by the FBI not to seize anything," Mr. Kuby said, "or somehow they missed the explosives that they were explicitly told to search for." In April, the imam pleaded guilty to lying to federal agents for initially denying he talked to Mr. Zazi and was sentenced to time served and ordered deported.
Spokesmen for the Port Authority and the FBI declined comment.
But Port Authority and FBI officials with knowledge of the investigation said there were factors that made the search of Mr. Zazi's car a touchy proposition. The Port Authority stopped Mr. Zazi at the behest of the FBI, which had tracked him nearly 1,800 miles from Colorado. To avoid tipping him off, they pretended the stop was a random drug checkpoint.
A Port Authority officer said police didn't have a warrant. That prevented them from conducting a thorough search of the vehicle without making Mr. Zazi suspicious. Anything seized from the car in such a search would have been inadmissible in court, he said.