Sister is torturing us

Hi Thanks a lot for making such a platform to help people. My elder sister has torturing and abusing me and my mother for last 06 years. I am working so I live in some other city now. My mother is at our home with her.She took my mother's mobile phone and her identity proofs. Things are getting worse with every passing day. Few days back she tried to strangle my mother and when my mother tried to save herself, my sister got a couple of scratches on her hand. So she backed off and called the police, saying that my mother is mentally unstable and attacked me. Though my mother handled the situation and explained the truth to the police but she left the home next day, fearing my sister might kill her if she stays. The house is in my father's name but he doesn't live with us. My sister left a very good job 02 years ago and moved to this house only to get rid of her expenses. Before that me and my sister were living together. And she did the same with me but not to this extent. We want my sister out of that house and get all of my mother's documents. Please help me urgently. Thank you so much in advance. SD