Not the end all be all, but where were these kids parents? And why were they not able to discuss what was goin on in school with them? I cant help but to think that with supportive parents who are involved in their kids lives, that things may have been different.
In the Columbine case, the guns used were not the parents guns, but guns borrowed from another friend who possessed them. Even though I think trigger locks are a good idea, I dont think they would have made any difference in this case.
I know that sound idealistic, but if you are "stable" in a comfortable enviornment, Im pretty sure anyone would deffinately think twice before even attempting to do something like that.