Can I be sued for slander in this case?

My stepdaughter came home from her mother every other weekend visitation with finger sized and shaped bruises on her sides. My family and I asked her what happened and where they came from. She said she was being and her mom had to tell her a few times to get out of the pool. She didn't listen so her mom grabbed her and squeezed her really hard. She said she wanted to cry but didn't because she was afraid her mom would get more angry. She has a history of inappropriate behavior towards them(starving them and locking them in closets). She also is mentally ill.I called the cops on her and filed a report. They took pictures of the bruises and statements from myself, my stepdaughter, and her sister who was there and witnessed the whole thing. The cops went to the mothers house and spoke with her.CPS told us its on file and that we need to follow through with the court agreement. Now she is bring tape recorders with form drop offs and pick ups and saying things to provoke myself and my husband. She got me saying she should not be abusing the girls and then she would not have to have the cops called on her. Could in anyway any of this be considered slander? and could I be sued?