I'm writing a fic where one character wants to try to find the family of another. He knows where Character B is, and is essentially trying to return him to his family after an accident. As far as he knows, Character B (who can tell him nothing) is an American citizen who was kidnapped as a child, some twenty years previously. Character A thinks that it's possible missing persons records might help, but he has no idea where in the USA Character B is from, he is not related to Character B, and he doesn't know if Character B was ever reported missing in the first place. I'm perfectly happy to accept that this is a doomed idea of Character A's that will garner no leads, but I'd like to have him make a stab at it.
Is there a USA-wide government or other organisation he should contact? Are there any obvious first steps he needs to make? He has some money, but not a great deal, and can get one reasonable favour from a law enforcement agency, due to contacts in his home country.
ETA: Google searches I've made suggest that the Salvation Army would perhaps be a good place to start, but for cultural, language and other reasons, Character A probably hasn't heard of them and wouldn't be inclined to get in touch.