How Can I Find Out if an iWatch is Stolen?

Hi,

I have been pretty much been played on Facebook Marketplace. I bought a used iWatch that was never unlocked. The person I bought it from sold it because she couldn't get into. (Would have been nice to know that.) When I asked for the original owner's information, she never responded. I'm afraid now it's stolen. Is there anyway to know if it's stolen? I'd like to get it back to the person it belongs to. I talked to an Apple representative over the phone and they said they have no way of knowing. I just find that hard to believe.