Thank you all.
Here the new facts: The boy was member of a sports marksman association, so it was easy for him to legally access the guns. But he was at the same time somebody with a preference for a special man-shooting videogame and heavy metal music with texts like "kill your teacher" and as far as I remember for horror videos. Online he called himself son of satan, you know what I mean.
He only wanted to kill teachers, the two pupils had been killed when he shot through a closed door.

What is the use for banning guns if this kind of people is growing up in our society? I mean, the guns are a tool that is easy to get, banned or not. We need a society that cares for the helpless, as I said above already. It is just difficult to see the signs, obviously he did not behave very odd before. It is always necessary to keep ways for everybody open to solve problems and to release aggressions. I think a gun ban would have a marginal effect, but there are more important things to do before.

__________________
If every material thing is gone, my smile and my tears stay left.