How to fight against this type of action

Today in Barcelona one teeneger had killed one teacher and had injured some students too. This teeneger killed the teacher with a crossbow.

As I see it this experience will change or is changing our point of view in laws and in education.
In my opinion, I think we don't have to work in secundary school security, we have to work in the way we are teaching our sons. This boy has some mental problems and possibly education problems . If his parents didn't noticed that is maybe because they weren't at home so, according to this point his parents need to be punished, but I don't know how.

Also, the boy isn't arrested because he is 13, and laws don't allow arrest him. But with my point of view he need to be punished, maybe putting him in a under 18 center.

I have some ideas for fight against this security problems; work on home moral issues, and also, work on what you can do or not. We should change laws,teenegers under 14 can enter to a under 18 center.

In my opinion I don't think that we need metal detectors in Secundary school or some policeman or security man who check out our bags or our clothes, because it will atempt to our indiviluaty and our privacity . This typ eof accidents are dangerous for that, it can cause privacity and indiviluaty restriccions, It had happened last month in Paris  and can happen today in Catalonia or Spain.

In conlusion , I think we don't need to protect us, because is unnecessary we need to work in our education for evite this situations