Theres no such thing as shooting to kill or shooting to mame.
If a poilce officer is at fault here it may not be the one who pulled the trigger. We don't know the situation, but if the officer with the gun was given the information that the person he was following WAS a suspect in the previousdays bombings, and he behaved like a suicide bomber, then the actions the officer took are irreproachable. Obviously this brings into question the quality of the information given, etc. The officer hasn't just shot some random person with a backpack.
The shoot-to-kill or shoot-to-maim arguement has been completed a long time ago.