Agree with thir. I wouldn't spend any more time around her, and would consider leaving a place she was hanging out and not interacting with her further. It may also be worth starting to gather documentation for the death threats and such. If you think she may continue then you should contact a (hopefully kink-friendly) lawyer and get some advice. Especially if she has a history of formal complaints and litigiousness you should document, establish a timeline, and get legal advice sooner rather than later.