Actually, the other two deputies shot the dog, a German Shepard -- which could certainly be justified if the dog was reacting to the gunshots.
Addtionally, the fatal bullet, fired by the formerly indicted deputy, was "tumbling" (ie, had struck something prior) when it hit Peyton Strickland in the head, so he probably wasn't obviously unarmed at the time.
However, indisputably, by law, officers can't shoot from the outside into an occupied home unless they believe their lives are in imminent danger.
My feelings? If the kid was really guilty of the assault and robbery then good riddance -- he had a prior charge back in September for "assault inflicting serious injury" -- he was a moron that would have probably fucked with someone else later on in his malicious insignificant life, and I'm content with him being 6 feet under.