If yo think you have been scammed, you can make a police report, but I would expect the authorities to tell you that it is a civil matter.
You can take him small claims court, if the amount involved is within the limits for small claims court in your state. Even if you win, however, you still have the problem of collection. And, of course, you will have to "serve him". (I think that he will conveniently "disappear".)
This one is problably going to be one of those "life lessons" that was learned the hard way.