At least 70 people died when a suicide bomber attacked a group of mourners at a hospital in the Pakistani city of Quetta. Lawyers and journalists had gathered following the shooting of a prominent lawyer earlier on Monday. Both Jamaat-ur-Ahrar (a faction of the Pakistani Taliban) and Islamic State claimed responsibility.
— from The Economist Espresso, August 9, 2016
One of them is lying. (Possibly even both of them.) The perpetrator is dead—we have no way of knowing for sure. Why give either of them credit?