When you get a substantial amount of evidence, report it to the police. Don't even confront her about it. There's no point. And you could try showing your family what's behind her mask, but she will retaliate. There really isn't much you can do in that situation other than go to the police and stay away from her. She may be able to "change" if she had different priorities or would listen to reason, but from what you've said, it doesn't sound like she's willing to better herself. Just be thankful you know what she is and haven't been lulled by the facade.