First of all, rest in peace to the people who lost their lives in the tragedy.
I realize how convenient it is to place the blame on two brothers who were walking through the crowd with backpacks on, but my critical thinking will not allow me to just accept this with the little proof available.
Where is the proof?
There are two sides to everything.
The first brother was "killed" last night, and so there goes one half of the story.
The other brother will most likely be killed as well, he's a 19 year old kid who has the whole country looking for him.
One look at his Twitter account, and you see he was just a normal kid: https://twitter.com/j_tsar