I find myself agreeing with the Capt. Cops are great at cleaning up, investigating and catching crooks. In the moment, one's self or one's fellow citizens are all you have. A bystander is of course not obligated to intervene, but if he is legally able to do so then he is permitted to do so, and
IMHO, should be praised if he does so. There's clearly alot we don't know yet about the situation, caliber, etc, but we know the outcome. Bad guy down, no innocents hurt.
The perp was using a lethal weapon to threaten another person while committing a felony. As soon as he pulled that gun he is a fair target for a cop, security guard or good Samaritan. If a cop or security guard had done the shooting there would be no question as to whether it was the right course of action. This guy wasn't a cop or a guard, but he was legally allowed to own, carry and operate a firearm.
Interestingly, if his story is how it happened than it's even more legally clear because he announced himself and shot the perp when he was turning on him with a gun. He probably would have been legally safe anyway, but as soon as the perp turned on him with the gun, he was clear to take him down.
I have a very high regard for life and am truly glad the perp didn't die. However, he had it coming, and if he had been killed he would have only himself to blame.
Anytime you pick up a gun to commit a crime, you put your life on the line.
I did find what the relative said unconscionable. She said the guy should have left the store, gotten in his car and driven away. No mention of calling the police?