Put the roscoe on someone

What does it mean to ‘put the roscoe’ on someone?

I know that ‘roscoe’ is slang for a gun, but I’m pretty sure from watching old movies that ‘to put the roscoe on’ means to kidnap someone.

My Google-Fu is not mighty today.

I assume it just means to aim a gun at someone (which you would generally do in kidnapping). In fact, in this passage it just means threatening to shoot someone.

Do you have some specific cases where it means to kidnap where a gun wasn’t involved?

I had never heard of the term so I went googling, but my google-fu wasn’t much better than yours. From what I saw though it seems like the term is just used to mean pointing a gun at someone.

If you are kidnapping someone, one of the best ways to do it I suppose would be to put the roscoe on them (point a gun at them) and make them get in the car or whatever.

Seems to be a 30’s and 40’s slang term. Were you watching old gangster movies?

This was my understanding, mainly from watching old gangster movies.

Yes, I think of it as a '30s slang phrase. No specific case I can think of, and I haven’t heard it in I-don’t-know-how-long. I do like old gangster movies, but haven’t seen any recently.

Absent context, I would have assumed it meant, “call the cops”. Isn’t Rozzer a slang term for cops? I’m not sure why. But that’s what “put the roscoe” sounds like, to my ears.

The Urban Dictionary:

Rozzer is British slang. Roscoe is American slang.

“They’ve been putting the roscoe on me now for a good many years and I’m still healthy and happy.”
-Al Capone, quoted in Capone, The Man and the Era by Laurence Bergreen

I’ve always thought it to mean to point a “roscoe” (gun) at someone.