Can you find a VIN on the car? If so, you can probably use this form:

http://www.state.nd.us/dot/docs/moto...e/sfn02903.pdf

All states are different. If I were in your shoes, I'd call the DMV, tell them the story (anonymously, of course) and ask them what to do. If you get a clerk that doesn't know what's going on, ask for a supervisor.

Once they tell you what to do, get a name of the person on the phone.