Oh no, he's no DB. I have already read somewhere that he was a victim of bullying.
While being bullied doesn't excuse any behavior, it can certainly explain it.
Especially when bullying typically involves the entire class or grade targeting 5 or 6 individuals who are different or don't fit in. Pack bullying is much more popular than good old individual bullying.
You push a kid hard enough and long enough, and their already fragile mind is going to snap.
Most people aren't physically capable of making a good rational decision until their late 20s or early 30s anyway. The mind of a 16 year old is chaotic and overly emotional to begin with. You lump a bunch of consistent abuse on top of that and this is what you get.