Sounds absolutely terrifying. I am glad you are out of there.

Have you ever met this person before?

I heard a lot of stories in real life and on here that when people only know each other online (both romantically and friendship wise), when they take a risk of staying in person’s house, things turn very differently than expected. Of course it’s not a rule. But sadly it happens a lot.

Sounds like this person didn’t show true self to you until you actually met her. There is no answer to why she did that to you. We simply cannot know. All we know that she is a horrible mess and you are lucky to get out of there.