Think this has been covered before. Marti report will provide where the car was originally sold to help start a search from the beginning end of the history. The following will work the search from the other (more recent ) end
1- Do you know where it was last licensed (sate) in the US? Some states will allow a history search. Many states will not have searches due to privacy and anti stalker laws
2- As I understand there are services out there (like private investigators) that will do a search, track down past owners and do on. Be aware that not all past owners will want to be contacted