If this chain of events had gone down between the deceased and a private citizen (say, you or I), we’d be looking at a murder-2 charge every time. It is well established that a “coup de grace” after the threat is ended in a self-defense situation is a crime.
A fleeing unarmed man being no threat in any serious sense of the word, the only real question before us in this case is whether a police officer is allowed to use deadly force as a means of apprehending a fleeing suspect.
Basic firearm instruction tells us that this is not the case. “Never point a gun at anything you do not intend to destroy” is the rule, any responsible weapons training makes this clear before the trainee ever gets to touch a weapon.
The job of the law enforcement officer is to apprehend suspects, not to destroy them. The reason that is so is that we at least pretend to have a justice system where a man is innocent until proven guilty and is allowed to present a defense of his actions before punishment is carried out against him.
It’s not as clear cut as that. Until 1985 a cop could legally kill any fleeing felon. SCOTUS narrowed the law via the Garner case but still allowed a cop to kill the perp if he considered him to be a serious threat to himself or others.
This is where it gets a little grey. Just moments before Slager shot Scott, Scott was fighting with him and had grabbed his taser. This made Scott a mortal threat to Slager. It was then that Slager justifiably decided to draw his gun and kill him. Slager’s mistake was in failing to unmake that decision once the situation changed and Scott started to run. But even then, you’re talking about someone who was willing to fight a cop and grab his weapon. What if Scott had run to the nearby pawnshop and beaten someone up?
You say that’s far fetched but consider the situation from Slager’s POV given what he had just been through with Scott. That’s why I think the murder charge won’t stick.