There's nothing new to say about this, but there's little else worth writing about today.
Words like sad and horrific can't adequately describe the horror of the murder of an eight year-old kid waiting for his father or the dismemberment of people at the moment of an athletic triumph.
Words like anger can't express the repulsion and contempt we feel for whoever is responsible for this.
I'm not the kind of person who finds comfort in the idea that this is part of some grand design by a deity and what kind of God would that be anyway? Certainly not one I'd thank and praise for anything.
The best word I can come up with is one that millions of others fall back on. It's all so totally senseless, though obviously it made some kind of twisted sense to those responsible for it.
So, I suppose the best we can do as a society is care for the victims, find the murderer or murderers, and punish them.
No matter what we do this won't be the end of violence. Terrorist bombings have been going on since the invention of explosives. The best question to ask is how we can reduce the pathology that underlies them.