Jeez, no, why tell anyone? How is that anybody else’s business? The wrong has been redressed in an unfortunate way, but it’s over, and there’s no further moral action to be taken. The overt moral justice is served and the case is closed.

Now, as to the subtle moral question of revenge, it’s quite tricky. We can be assured that to take out the cop while in pursuit (on route to the ill-fated Dave) is wholly moral as a preventative defensive action.

However, just a mere instant later, with Dave unsavable, do we have an obligation to spare the aggressor (perhaps capturing him) with hope of rehabilitation - a second chance to become a moral human being?

I tend to prefer that outcome, yet I do not believe John has committed a moral crime by exacting revenge. However, it is no longer defense proper, which raises the question - is there a moral imperative to refrain from justifiable defensive action the moment all hope of defense is lost, and no further threat can be clearly discerned?

It seems to be a middle-ground (which may simply reflect the limits of my moral understanding) whereby the revenge is not morally punishable, yet may not be wholly moral either. To claim John’s action immoral is to say that it would be moral had it come sooner, but no longer is. This would seem to obviate the notion of redress altoghter.

If the action was just before, it must always be just. The violation of rights imposed a stain - a scarlet “A” for “aggressor” - that cannot be removed. In that moment, he incurred karmic debt. The consequence of that action lingers; it does not utterly disappear the moment the victim is killed.

If the aggressor can be punished a second after the act, he may be punished at any time. Moral consequence does not dissipate over time. One would have to assert that punishment is never justifiable in order to argue against the deferred revenge - even in a case where a person kills 10 people, then throws his hands up.

Is it only about eliminating an imminent threat, or is justice served by revenge? I’ve made a case for the latter, but also presented considerations about the former that must be considered in earnest. I, for one, believe I could benefit from more discussion about the subject of revenge.