There have been a lot
of these types of scams over the years--I can't even tell you how many different ones I've cleaned up on people's computers. They are pretty common: infect the computer, put up notices about how it's infected with viruses/spyware, then charge the user some money to "fix" it.
The stupidity here is that an American did it. You can't get away with that. It's usually Russians who are big into this kind of thing--not much legal recourse an American has against an anonymous Russian.