Problem Teen

Mi- My niece has runaway and its not the first time but it is the longest. Her parents are worried and searching. Her boyfriend has said that he has been in contact but doesn't know where she is. Everytime she gets grounded she runs. We have had eye witness accounts that she was seen with her boyfriend but no one willing to tell the authorities. The boyfriend's family has a bad reputation and many criminal records. We believe she is at their house but can not prove it. The police have questioned them several times. The police advised her mother to charge her with incorrigibility but is that the right thing to do? and its only goes into effect if she's picked up. When she is home she wreaks havoc with the household but her mother doesn't want to allow her other children to think that this behavior is acceptable either. My niece has been in therapy (individual and family) for eight years but nothing seems to help.She has been told by the police that she is responsible for her daughter's actions regardless of whether she ran away or not. How can we get her away from that family and their bad influence on her? How can we get her home where she's safe?

I am new to this site, reading all post's "Hoping to find a answer to my dilemma", and have noticed your name several times, to different problems?? Am i correct in this? If you are familiar with the way's of this site, PLEASE... Help me!!
And, why are you on here so much?: confused: RRR