Why did this person delete me from facebook?

I graduated high school 2 years ago. There was this kid who I wasn't friends with in my class, but we always spoke to eachother and were in a few classes together. All of a sudden today I find accidentally that I've been deleted from his page. I never did anything, I was always nice and cool with him. I don't understand, we went to high school for 4 years together. A couple of months ago I decided to write on his wall to see how he was doing cuz I hasn't spoken to him in awhile, he never replied and deleted my whole wall post. I did notice however that his profile was a picture of vandersloot, the man that murder the girl in Aruba a few years back. Vandersloot and him look alot alike and I thought it was weird that he would have a cold blooded killer as his default. I never said anything tho. I'm so confused, it appears he kept the rest of the class but me.