This is a horrible atrocity. It should be unthinkable to do such a thing. This said, my big concern is that we're going to see copycats within the next few weeks.
The media ensures that the perp will get his 15 minutes of fame. I don't know what kind of sickness prompts people to think "Hey, I think I'll do that, too", but we've seen it happen before. There were hundreds of copycats after Columbine - the vast majority detected before anything was done. I would like to see the media change the way they report these events. There are more important things than viewer ratings and advertisements at stake here.