You can call the cops but unfortunately they can't do anything other than maybe talk to the psycho girl's dad. I know this because I have a neighbor who's been trouble since my mom and I moved in, he's got anger issues (and we believe he smokes pot). But he's yelled and screamed at us every name in the book, we finally called the cops and they couldn't do a single thing. So dissapointing.
I'm really sorry about what happened. I had trouble with bullies when I was younger and it's no fun. But mean adults are the worst.