Ummmmmmm, and what, exactly, are the police in Kingman AZ going to do about a guy who has gone missing in Romania?? Not a police issue, boys and girls. If you're concerned, call your representative to help you contact the embassy. They'll have access to customs records to see if he ever made it. If he passed while in a foreign country, that country should have contacted the embassy with his info. If he's still out and about, they'll at least know if he legally extended his stay. They'll know if he's in jail there also
Do you know if he has any family? Anyone you can notify? IF the cops haven't shown up to his house, most likely, he hasn't been reported as dead. If the US got notice of that, they'd send a teletype to his local department and they would try to contact living relatives at his last address.