One of my main protagonists, an NYPD Homicide detective, does a bit of after-hours clandestine work to try and prevent a murder, i.e. he spies on the chief villain and a couple with whom she's engaged in sexual/BDSM activity. He knows the husband of the chief villain is going to come home and start shooting (and the husband is an old friend of his), so he bolts to the nearest phone booth to call the cops on duty to come and arrest her. (She is also prime suspect in a murder investigation).
My question is this: Would the Detective Bureau, in this particular case Vice, have had men on duty at night (outside of them working on a major case)? Or was it uniformed officers only who regularly worked the graveyard shift?