I am not entirely certain that the police wouldn't at least be willing to make a phone call to try to scare the guy into coughing up the title. If the seller intended to do this from the get go it would be a crime. If the guy sold him a stolen car that would be an issue as well. I too doubt that the DMV can do anything because the car was titled out of state and therefore the DMV would have no records indicating that the guy that sold it really owned it.