The story is the VC fired an RPG, they shot up his position with 50 caliber, they VC starting fleeing and either he was shot then or was already injured. I've seen no evidence the VC had any more grenades or was preparing to fire again.
What are the military rules for an encounter like this? If he is injured and offering no resistance, is Kerry obligated to capture him and return him as a prisoner?
Not being a grunt or being in Nam, I wouldn't know the specific ROE (rules of engagement)...other than it's always been okay to kill retreating enemy. So I have no problem if Kerry shot him the back as claimed, nor if he were a teenager, so were ours. Until the enemy lays down there weapons and throw their hands up, they're fair game.