This story looks self explanatory.
What a horrible tragedy. It's all I can say.
Nothing can really be said that we haven't all said before. It's heart wrenching that we have to keep repeating these events; like some kind of surreal bad nightmare. Whatever the cause, whether mental or ideological, it's the human condition and it seems that we have no way to control it. If it hadn't happened with this person at this time, it would just happen with someone else on a different day. I wish I had reasons to be more optimistic.