Suspected child abuse?

Br

Thismight be long but I am desperate to know what I’m suppose to do.

A month ago me and my mom went to pick up my nieces. My sister was staying with her sister, when we arrived the house was filithy (cat feces on the floor the whole house smelt awful) there was my 3 nieces (who we picked up) and my sisters sisters 3 kids (16m,13m and 11f) in a small 2 bedroom apartment! That’s 8 people!

Besides that when we showed up the police showed up because the 13&11 year old haven’t been to school in over a month!

Now this is where I’m concerned. I took my youngest niece whos 19 months, she’s horrified to be touched in her sleep, she’s scared of her own room, horrified of men, and when she will sleep in her room she lays against the door.

My mom said the middle child was too much and dropped her off woth me yesterday. Where she has told me she has a baby in her belly? We know she was physically abused by my sisters ex boyfriend. She was taken to the hospital with a fractured arm and bite marks all over her in the past. She’s very scared, thinks there’s monsters, refuses to tske her clothes off in front of me or anyone else, she isn’t potty trained and screams when I try to change her, she constantly gets scared when she hears anything (a dog bark, the tv, the doorbell, the microwave)

I don’t know who to take her to or what to do

My only custody paper is a copy of a hand written note signed by my sister because my sister refused to have any offical court or notarized doc. I don’t have her birth certificate becsuse she never got one.

The reason we took them is because my sister lost her section 8 apartment because it was dirty and my sister was never there. My sister has never had a job and she needed us to take them so she could get one and save up to move states.