Been following this thread the whole time....
Wow.
Videotape the entire encounter, if you can. I'm serious. You can delete a file later if it doesn't pan out. If it turns into a situation, it's the best thing you can possibly do to help put your sister in her place.
I was disgusted as I read this thread. Disgusted.
Do you live with her? If not, there is no way she would ever be allowed to set foot in my house ever again. Ever. Family or no family.
If you do live with her, I would seriously urge you to get a locking door for your room, and keep it locked whenever you are not in it.
How can people honestly think that that type of behavior is okay?!
I really... really hope that your sister gets identified and that people start listening to your side of the story.