Thank you all for your kind comments
As Maggie pointed out is his identity confirmed. Today it's became clear that he had psychological problems and has been threated before in a psychiatric hospital for suicidal potentials. Those records were known by the police so why he got an police permit for having weapons is a riddle.. He was clearly an loner, no friends or family.
Blaming the police or spitting his past won't change a thing about what happened. The only thing we can learn is that psychiatric patients need to be taken very seriously. You don't get a safe society... but the people who suffer from the inside need help.
At the moment there's is an commemoration. I don't only hope people will be able to overcome this loss, I hope this won't create hate and indifference in the people's hearts. There's already so much of it.