Decision making rights of a 16 years old.

This girl who is 16 years of wants to be with me because of all the torture she has been going through in last many years. Her family abandoned her 2 months ago. She has been living with me, I have been responsible for every small need of her since then. Now suddenly her brother and mother are forcing her to leave me and go with them. She dont want this to happen. They are mercilessly forcing her. We went to seek police help and police said she has to go with her parents and if she doesn't , her family can drag me into kidnapping case. I have always taken her as my daughter and now she dont want to leave me. They are such cruel people, his brother in police station said let her come to home once i will cut her into pieces. He abused her and was trying to take her forcibly. Some how i have kept her with me tonight. We are called at police station tomorrow. We need some serious help. Please suggest something, i cant let them take and toture her again.