Dirty bomb or chem bomb on the bus?
White powder all over people? He said what it was, but I missed it. Total mess....they won't even admit it's terrorism. Might be a copycat. I pray for the poor people in the middle of this TERRORIST attack.
Could be just the unstable but unexploded remains of the bus bomb. Since they've said this bus bomb appears to be of same design as the bus bomb of 7/7, that would strongly suggest that it didn't fully explode(given the roof is still intact.)