Federal agents knew that a would-be terrorist had likely arrived in New York City from Florida over Thanksgiving weekend in 2012. However, they didn't know where in New York City he was — a worrisome prospect, considering that Raees Alam Qazi was gathering information on the best places to detonate bombs in Manhattan, Times Square and Wall Street among them.
The NPYD's Intelligence Division, it turned out, knew exactly where to look — because it already knew places in the metro area that might be inclined to open their doors for the night to a cash-strapped transient enamored with al Qaeda. It then sent an NYPD undercover officer into one of those locations and confirmed Qazi's presence there. That allowed federal authorities to initiate surveillance and arrest Qazi on terrorism charges as he stepped off a bus in Ft. Lauderdale on his way home soon thereafter.
Similarly, as Seth Lipsky reported in Thursday's Post, had the Boston marathon bombers made it to New York with their explosive devices, the NYPD would've been in a good position to know where to look for them because of some mapping it had done in Brighton Beach and elsewhere.