Is there any legal background against bit coin cheaters,who using scam sites for cheats people..
Yes you can file lawsuit against scammer. The problem is having a strong evidence to file against them because if not your filed case will be nothing. Scammers are hiding their identity using VPN and some app to become anonymous. Remember that we are in online and bitcoin is for anonymity transaction. It is hard to determined who are the real scammers.
This is how its just like to have some pointless actions if you did try to make such step because they wont really easily believe you if you don't have proper or enough evidence into a certain scammer which isn't know yet. You cant just give them a bitcoin address since it wont really be a valid thing.This is why bitcoin is a good vessel to scam people because of its untraceable behavior if you can able to trace out then your lucky but most of the time I do strongly believe and I'm 100% sure that you will surely fail. This is why once your coins are gone then don't hope that you would able to recover it back.