My father is in the process of a rather bitter divorce
. My stepmother has two daughters, the eldest has a history of drug abuse, stealing from our family, is extremely disrespectful and belligerent, and a younger daughter who is equally disrespectful, belligerent and has a violent temper. My stepmother has done nothing to control their behavior. My sister and her boyfriend reside at my fathers home, a home that is a joint ownership between my Dad and stepmother. My stepmothers youngest daughter also resides there. This past weekend, my father, who is working several hundred miles away, came to visit for the weekend. The youngest daughter ranted and raved with a foul mouth and threats toward my father, sister and her boyfriend for well over an hour and a half. She was extremely violent, intimidating and we are wondering what is the "fine line" between a person "running their mouth", compared to and an outright threat is construed as by the law, and when the police should/or can be summoned to address the issue if she behaves like this again. She is over 18, is a guest in their home, just as my sister and her boyfriend are. I need to duly state that the youngest daughters behavior is not an isolated incident. She has a history of this type of behavior, has purposely damaged and vandalized my fathers car, she has caused a great amount of stress to my father, sister and her boyfriend, and again, my stepmother has done nothing to control this behavior.
What are our rights as a family to protect ourselves from this repeated verbal abuse, and in terms of recording this on tape or video, is there a consensual element that needs to be satisfied in order to be admissible in court? How can we record the behavior legally to use it, to demonstrate the vile behavior we have had to endure. Also, are there any "key words" that we need as a signal to summon the police when she becomes like this?
Any help and insights is most appreciated.