Outer Circle: Schoolgirls poisoned in Afghanistan

In northern Afghanistan, more than 120 girls were poisoned in their school. Attackers used an unknown type of spray at the school that resulted in fainting, dizziness and vomiting. It's the latest in a string of poisoning incidents targeting girls schools in Afghanistan.
We asked CNN's Nick Paton Walsh who is covering the story in Kabul,  if the Taliban is behind the attack.