My freshman roomate was 16 at the time.
He was a nice guy but he fit basically every characteristic of the socailly awkward loner type that would go on a shooting spree. He even had a bit of a random temper (he never snapped at me but got pissed at other things)
I guess that's what happened when I mentioned that I liked listening to nine inch nails and wwf wrestling on my survey when the college matched up roomates.
Fortunately he never came back after thanksgiving break (it was for the better, the kid was clearly uncomfortable at school). I hope all is well with him and figure it is but he does sound alot like these shooters