It's a mental game; whoever did this is trying to demoralize us.
It's not North Korea. They aren't that stupid. I'm going to assume it's a terrorist attack because it was a 2 bomb coordinated attack.
It'd be ridiculous to even think that North Korea would do this, that's not what I meant. I assumed it was a terrorist as well, but it just doesn't make sense if it was one to bomb some marathon just for casualties. There's no political statement, no scare tactics, just a massacre. Might just be someone who gets off on killing civilians.