It's an audiotape the New York Police Department hoped you would never hear.
The caller, Salil Sheth, 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 lie low and coordinate surveillance. Since the Sept. 11, 2001, terror attacks, the NYPD, with training and guidance from the CIA, 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.