Give the man a medal for taking out the trash.

 

Police generally shoot to make a BG stop whatever they were doing to get them shot. Easiest way to make them stop is catastrophic disruption of central nervous system. Mere coincidence that this means "2 to the head, you know they're dead."



BTW, shooting at a leg is both a horrible idea as a way to prevent killing the shootee, and way more dangerous for bystanders than shooting for center of mass.