I think you're probably misinterpreting the quote. Here's the reporting on this from the NYT:

Mayor Eric Adams said Friday morning that the investigation was “on the right track.” In an interview on Spectrum News NY1, the mayor added: “This person was fully masked, and we used good old-fashioned police work to come up with the picture you have.”

I think what the mayor is saying here is that because the alleged killer was masked, the cops actually had to do some detective work, canvas door-to-door maybe, pull security footage, that sort of thing. It wasn't just a case of sitting back and running facial recognition on the killer like something outta CSI.

Unless you're thinking of a different quote.