He killed both of his parents. I'm guessing that he was either abused as a kid or he had severe mental issues that the parents could not deal with but he blamed them anyway. Maybe he resented the fact that his mother was working with kids while he was struggling with problems that were not being addressed.
I agree that he was a coward first and foremost. Although they have not as of yet released much information, I feel pretty certain that somehow it was a retaliation towards something within his family, specifically his mother, since she was a teacher at that same school, but again, I am just assuming. Also, what was up with his OLDER brother being with him??? Yes, he was a coward. Plain and simple. I am not going to blame this on his being abused or molested as a child. Plenty of children are abused and do not grow up to do such things. That is a cop-out. I had PLENTY of childhood issues bordering on child abuse and I have not turned into a serial killer. ijs And, if it were mental issues with him, what was his brothers excuse for being there?