Why do students kill in their school?

Yesterday there was another case of a former student who went back to his school to kill teachers and children.

The 17 year old young man in Germany appeared to have no reason to be so angry that he could take the lives of others, so what is going on?

This latest mass killing is just another in a long line of student killings where the killer seeks to exact revenge on a real or imagined slight on their character. Invariably the killer himself (it is, so far always a male) is also killed.

In the past, some of these killers were on medications for depression or learning disorders and it prompts the question, did the medication make things better or worse? Did it hide what seem to be suicidal tendencies or did it make them more apparent?

Since any person embarking on such a mass killing knows that they are likely to killed themselves, it does appear that this is an extended version of what Americans call 'suicide by cop'. This is where a person engineers a situation that they know will end with their death through being shot by the police; for example by taking a hostage.

So is this a suicide where the person involved believes themself to have been so cheated by life that the only value they feel they have left is a posthumous notoriety that they will never be aware of?

What ever the reason it is a tragic aspect of the way we live today.