One day I was walking my first dalmatian ( i am on my third) called “Dasher” in NYC and a real screwball with a couple of friends stopped me and demanded I hand over the dog to him. He said the dog was stolen from him and he wanted it back.
There was no way I was handing my dog to these guys and to make a long story short I had to actually show the police the ownership papers.
Fortunately you were able to prove ownership! Too bad that they tried to steal your dog from you.
I’m surprised the officer didn’t ask the guy who approached you to call “his dog”. Since the odds are against him naming your dog by his actual name, it would be unlikely that your dog would leave your side to approach a stranger—especially a stranger whom he would perceived irritated/angered you by his demands.