"I smell weed" has been a classic for decades.
A long while back, I was harassed by the cops for "acting suspicious" while waiting for some friends at the mall. This quickly escalated to "suspected terrorist activity" for absolutely no reason I could discern or anyone afterwards could explain.
Cops just say shit. The best you can do is say you need to speak to a lawyer and clam up after that.
The department is administered and governed by the police commissioner, who is appointed by the mayor to what is, nominally, a five year term.
Can Zohran fire the existing commissioner and replace him? Idk what the bureaucracy around that looks like. Entrenched power structures have a way of slow rolling executives thru don't like and ignoring rules they don't want to follow.
A lot of levers of power that worked for a Guliani or an Adams might suddenly stop working assuming Zohran can make it all the way through the general and into office.