It wasn’t in the cops home and he wasn’t an intruder. The cop screwed up and murdered this guy.
It would still be legal if they were a civilian in a similar circumstance in states with Stand Your Ground laws. Unfortunately the second the guy swept a hand to his waist, that was it - game over. While the whole rest of the episode was atrocious and his training officer *and* supervisor should also be fired, I unfortunately must agree with the jury that the shooting was technically legal.