If you know someone is involved with a person that is a liar, cheat, violent temper, do you tell them?

This man claims to be kind, gentle, well educated, etc. and is a liar, mean, has a violent temper, committed his first wife to a nut house in Russia, raped a 16 yr old girl... and now has married another innocent woman based on lies. I know what he did to his last wife who was lucky enough to escape him. Do I let this current woman know what she is dealing with?

If you know someone is involved with a person that is a liar, cheat, violent temper, do you tell them?
Tell her, but don't expect it to do much good at first. If she is in love then she will be oblivious to what you say. Why didn't someone warn her before she got married or when she started dating this guy?
Reply:that is a double edged sword, she may hate you for telling her and takes his side, she needs to see some signs, make her beleive she is seeing the signs on her own
Reply:pickabombom is right. get some hard proof...like a police report, etc. first. Good luck.
Reply:you can tell her once only...if she does not hear you then maybe she would feel...if she is your friend or your good acquantaince she should believe you...if not then stay out their business and she will eventually find out...hopefully b 4 its not too late.
Reply:Do you have proof? She might listen better if you have some. If she is your friend you should tell her. I lost a good friend by telling her the truth about her boyfriend and later when I ended up being right she had no one to blame but herself. She might not listen to you at first but she will eventualy, and she will be thankfull.