Are you seriously reporting them to law enforcement? Doing so from where I am from, people would start laughing and take me for a lunatic. But if you have had any success do let the forum know because this would be a lively discussion for sure.
But the bottom line is pretty clear : bounty hunter became bounty hunters because of their own choice. So they have to suffer the consequences of their choice.
Is it possible that he will report the scammer to law enforcement in his country and how will the local law enforcement respond to this case.
Instead of paying attention to this problem, it is better to increase knowledge to make the top choices of projects that are worthy of being campaigned by bounty hunters.