I have a 15 yo foster daughter that came to me almost 2 years ago with severe neglect, sexual abuse and medica?

l neglect who has had a severe lying and stealing problem in addition to discipline problems. She goes through periods of good behavior, and then starts on a run of trouble, usually involving other kids. She recently began claiming a certain girl pushed her into walls and down stairs, and while receiving consequences for that, upped the ante and claimed an inappropriate contact from an authority figure in one of her classrooms. It was proven with video, that NONE of the accusations were true. I am at the end of my rope to come up with an appropriate set of consequences. She was already on one day of ISS and two weeks of restriction and additional chores when the incident with the teacher occurred. She was given 3 days of OSS and is now back in school. What do you think I should do for consequences at home for her 2nd offense? What can I do to be effective in getting across how serious this is? I feel she is only sorry she got caught lying and that there is no regret for what she has done or what could have happened. She turns 16 next month and is in the 9th grade. She has an 80 IQ and has severe emotional trauma, has been diagnosed with bi-polar, PTSD, depression and a host of other mental health issues. Am I wrong to be concerned that this one cannot be helped? There is also a potential for adoption which I am now beginning to think I do not want to do. She appears to be a sweet little angel on the surface, but underneath a very angry unstable child. She receives counseling from 2 separate counselors and a psychiatrist, in addition to medication. Any thoughts anyone? She has tested on the Cannes lately at a level 4, although the decision was to keep her in my home, I am unsure that is going to work much longer and now have had to resort to arming my doors, pantries, the dogs kennel and my room with alarms and locks after she almost killed one of the dogs and also began making statements about wanting to hurt herself and me. She has since claimed she would NEVER do that again. But my vet bill to save one of the dogs was well over $900 and I am still sleeping with my doors bolted. She is presently not mainstreamed back into classes without video cameras and there is a distinct possibility that teachers will not want to be alone with her (totally understood by me) and we are now working with her in a behavior modification setting until she can be returned to normal classes, IF she can behave, not tell stories or get into trouble. She says she did it for the attention. Now that she has it, she doesn't want it. Thanks for ANY help you can offer, I am at a loss as to how to get through to her how serious this is!