Yes, you and I have been over this before, but I'm a little more inclined to see things your way at the moment. These kinds of things are just horrible!
What confuses and concerns me about them is that there is very little in common among the shooters. Some were bullied and ridiculed, some were just shy, some were trying to settle romantic scores. Nothing concrete that you can come out and say, "Look out for this behavior in students!"