During a routine inspection, Salil Sheth came across a sparsely furnished apartment containing pictures of terrorists, photographs of local landmarks and Muslim literature, the building supervisor called police, thinking he had stumbled upon an al-Qaeda terror plot.
What he actually discovered was far less threatening but much more embarrassing – for the NYPD.
For Mr Sheth, who manages an apartment complex in New Brunswick, New Jersey, had inadvertently walked into a base for undercover officers investigating a terror cell.
The telephone call, in which Mr Sheth reported the discovery to New Brunswick police, has only just been released after The Associated Press news agency mounted a year-long battle with the NYPD