NEW BRUNSWICK, N.J. -- He saw something. He said something. And he inadvertently uncovered a secret spying operation that the New York Police Department was running outside its jurisdiction.

In June 2009, a building superintendent at an apartment complex near the Rutgers University campus opened the door to unit 1076 to conduct an inspection. Tenants had been notified of the inspection weeks ago, and the notice was still stuck to the door.

He turned his key, walked in and immediately knew something was wrong. A colleague called 911.

"What's suspicious?" a New Brunswick police dispatcher asked.

"Suspicious in the sense that the apartment has . . . no furniture except two beds, has no clothing, has New York City Police Department radios," he replied.

"Really?" the dispatcher asked, her voice rising with surprise.

The caller, Salil Sheth, and his colleagues had stumbled upon one of the NYPD's biggest secrets: a safe house, a place where undercover officers working well outside the department's jurisdiction could coordinate surveillance.

Since 9/11, the NYPD has monitored the activities of Muslims in New York and far beyond. Detectives infiltrated mosques, eavesdropped in cafes and kept tabs on Muslim student groups, including at Rutgers.

The NYPD kept files on sermons, recorded the names of political organizers in police documents, and built databases of where Muslims lived and shopped, even where they were likely to gather to watch sports.

The AP previously described the discovery of the NYPD inside the New Jersey apartment, but after a yearlong fight New Brunswick police released the tape of the 911 call and other materials this week.

"There's computer hardware, software, you know, just laying around," Sheth told the dispatcher. "There's pictures of terrorists. There's pictures of our neighboring building that they have."

The call sent New Brunswick police and the FBI rushing to the apartment complex. None had been told that the NYPD was in town.

Drawing rebukes from New Jersey Gov. Chris Christie and some members of Congress, the NYPD has infiltrated and photographed Muslim businesses and mosques in New Jersey, monitored the Internet postings of Muslim college students across the Northeast and traveled as far away as New Orleans to infiltrate and build files on liberal advocacy groups.

NYPD's deputy commissioner for legal matters, Andrew Schaffer, has said detectives can operate outside New York because they aren't conducting official police duties.

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