I saw humans running to help victims of the blast, disregarding their own safety, or unaware the danger they could be in. I saw the very goodness in humans that pushes my own cynicism aside.
And before the scene had settled down there was hateful things I read about Muslims. A Saudi Arabian who was injured was a "person of interest". Later he was cleared. This could be the act of a radical Muslim or two. However, it could be the act of someone like Timothy McVeigh, Ted Kacyznski, or other non-Muslims.
It is something troubling about these days we live in. Our minds go to dark places when faced with tragedies. Placing blame has become far more important than supporting the maimed in these events, or remembering the dead.