When it comes to mass murder, I've always thought that sometimes people are just crazy. But those that go looking for motives or reasons, are almost always guaranteed to find some:

Relatives told the St. Paul Pioneer Press that Weise was a loner who was often teased by others. They said his father committed suicide four years ago and his mother was living in a Minneapolis nursing home because she suffered brain injuries in a car accident.

Police are still putting together the details, but Weise apparently murdered his grandparents, stole his grandfather's police issued firearms, and went on a shooting rampage at his school. He ultimately committed suicide.

UPDATE: CNN's poll asks "What do you think contributes most to school violence?" 'Bullying' currently comes in at 44%, with 'Family Problems' a close second at 39%.

Of course, I always thought that bullying was school violence.