This wasn't random. I see and work with people with mental problems all day. Most are complete non-violent, but there are a few who go off and go off with guns. Last week a guy I liked who was getting himself together ended up in a shoot out in the Tenderloin and killed three people.
He needed real counsiling, along with a peer to peer groups and other `mental health' support. Nada. The healthcare system only pays for extreme cases requiring hospitalization. So nothing is done until the problems are so severe, they have become `dangerous' to themselves or others...
CG