Years ago there was a young woman killed in our area. Her killer had her phone and continued to use it to contact her friends and family to convince them she was alive and fine. Some of her friends and family felt the communications didn't sound like her and called the authorities, who then discovered she was dead. That type of thing is very rare. Odds are your daughter is "ok" and just making some bad choices in her life right now. But if you really are worried that she might be in a dangerous situation, you could call the police to do a "welfare check" on her...they'd make contact, establish if she's OK or not. Or are there any friends of hers that could confirm for you that they've seen her and spoken with her and she's OK? If you verify she is alright, just not living the life you want for her, then you need to accept her choices.

If you do have someone check on her, authorities or otherwise, she might very well get angry and be driven even further away from personally, I wouldn't take that route unless I really felt I needed to.

Good luck...that has to be awful being so worried about her and no way to get peace of mind.