Problems with a stocker / previous stocker?

Yikes. Well, stalkers are never good. Apologize to the other kid if you want (even though it wasn't your fault) and for this new kid, tell him to leave you alone or you will bring other people into this. Always bring friends, family, faculty, etc... into the picture so that he gets the idea that messing with you is not a good idea. I'm sorry that you have to deal with this, and I don't really know what else you could do.