Dib was outside your window, covered in blood while watching you sleep. This was his 4th murder and each time he killed it seemed to get worse. Dib had been watching you for a few months now and he soon realized he was obsessed with you and that he would do anything. And anything meant anything "Soon you'll be mine..." He whispered

Everytime he sees a boy talk to you in school that night he kills them. That's one of the main reasons Zim hasn't been around.