If you go to the online white pages and look up a name, ads will appear for commercial people-finding services. It will cost you about 75 bucks or so to put them to work. I once spent the basic $20 to get the name and neighbourhood of an imminently suicidal guy for whom we only had a cellphone number and that certainly worked. (But he had already taken off for parts unknown and we still don't know if he's alive or not.)