Who has rights over my step daughter and What do I need to do to get guardianship of my step daughter after her father was incarcerated last year

My 3 year old step daughter father chocked her so I had him arrested he has been in prison for over a year now. DHS left her I'm my home. She has lived here since a 1 1/2. And didn't​ open a case. He has his rights and the mother lost hers. He sent me power of attorney for her. He got mad and had his friends come and get her. DHS said since he has his rights I had to let her go. He sent them power of attorney after he had her removed but mine was never revoked. I supported her for over a year alone. He will be gone for awhile. So how do I get guardianship of her. And who has the power of attorney over her me or the friends. And if me can she come home.