I would take it to the police without her knowledge but still use it as a threat - she doesn't have to know everything.
Police deal with this all the time. I don't think they'll make you go full disclosure anyway.
I do know that minors do have some rights - where parents are kept in the dark. It is shocking I know since we are paying but that happened to us also but I cannot remember exactly what the situation was.
I think my mind glosses over details to help me cope.
