So lost, what do I even do?

Okay, so first, he's a psychopath. Just...yea...anyways, we dated for a while, then we broke up. He got really creepy and obsessive and CARVED MY NAME INTO HIS ARM with a blade. Now he's being all weird, and trying to be friendly. But I also forgot to mention, he is my best friends best guy friend, and they're always together. Today, he kept asking for hugs and coming really close. I got pissed off and sent him a really mean message basically telling him that there is no way were getting back together. Oh, and he HAS A GIRLFRIEND, and she's in a psycho hospital, and if she finds out, she may kill us both. Anyways, I need advice in what to do. Please please please help.

stay away from him