Connie and Andy, shouldn't work, but it does, and it's the best, makes the show more than just a police drama. Wonderful writing, love the instant comebacks, New York humor is the best.
Decades ago there was an episode of NAKED CITY - the story line involved a civilian who would dress up as a cop and pretend to be on foot patrol. On day, there is a shooting on his beat, and the saga slowly unravels. The fake cop was Stephen Hill, and the shooting suspect was, I think, Dustin Hoffman, in two small scenes.