Pah. Horrible kids who need to learn alot of respect and their place as CHILDREN. They must learn that life doesn't always go their way, far from it, and respect their teachers. Anyhow, those kids are most likely doomed, if there is any justice in the world. They'll bloom into the street trash that they've made themselves out to be, and end up dead in some gutter or crack house.
Does seem like an isolated incident, but by no means is it rare in alot of places for lowlife, scumbag kids to bully their teachers. I would advocate returning the cane to schools, but that would be a step back. Rather, expulsion and more use of rewards and non-violent punishments schemes, etc.
Really, I'm not surprised by it. Some nasty scum have killed their teachers before.