Is there any legal background against bit coin cheaters,who using scam sites for cheats people..
Scammers are committing a crime so they are liable to be charged in almost any jurisdiction, the problem is going to be to put an identity behind the crimes, you will need to make a research and try to find clues yourself, while there is probably a cyber crime unit in your country most of the time they concentrate in crimes that can harm people, like drugs, so you may not find a lot of support from them if the only thing you lost was some money.
Well that's the harsh reality,apparently getting hacked and losing your investment whose source was your hard earned money won't be treated as a priority by the judiciary system