I need help...

I need some help. My sister is hanging out with guys that are 10 years older than her, and they have raped other girls before. These people also do drugs (hard drugs). I don't know how to get through to her! She won't listen to me because she thinks these people are 'cool'. Does anyone have any suggestions?

Intervention! tie her to a chair and ... never let her go!! o.O
I really dont know but i wish i could help cuz thats not good. =S

i have an idea =) write her a long letter, full of emotion and detail. give her all the information, the positives and negitives of hangin around with these guys. well thats all ive got, hope it work

i have sat her down, and cried, saying i was concerned and stuff...i told my parents and they dont do anythig about it b/c they are 'giving her her space'.(mainly b/c she was suicidal before and now they are trying to suck up). I honestly am clueless