Back the parents authority with a few reservations.
I disagree, but I know a little more about this situation.
Rekless, she is in a dangerous situation at a very vulnerable time in her life. Invite her to live with you. Pay her way, even if you have to wire money to a Western Union for her to collect.
I don't think she should continue to be exposed to the type of activity you know she is being exposed to. She is in a 'grey' area of the law. I don't think she'd be considered a runaway if she came with you, but check with Law enforcement first.
Lisa