The White Elephant in the room....

I wish it weren't true. But it is- my 13 yr old daughter is a sociopathic teen who has violent tendencies along with a passive aggressive MO and a healthy dose of emotional blackmail. She has been actively attempting to get her stepfather to leave for nine years- all she achieved was a .06 GPA for the last two years straight in jr high. She hasn't passed math since fourth grade. When she was younger, (11/12) she had run away multiple times. Recently, caught fire to our carpet under the pool table. She killed our two week old kitten, was caught red handed strangling a neighbors cat during a birthday party, & put her 5yr old sister's life in danger multiple times. She has stolen/cheated/lied/&manipulated me and my husband, my sister, and countless other people she's encountered. I'm fed up and all I keep seeing is "get the sociopath out of your life." How do you do that when it's a dependent?? I refuse to be a victim. I am really ready to plan an offensive. What else are my choices? Lying and taking it isn't who I am. I am a confront your problems person, but the medical people always say not to let them (the abuser) know your plans or weakness. I'm so stuck......