Nuremburg saw the Nazi heads tried for warcrimes and executed, who is to say Ukraine never held a trail for his war crimes in his absence, found him guilty and executed him.
Executed? He was a member of the military who was killed by the enemy - that fact that he was shot in the street is no different than if he had been hit by a drone on the battlefield. With, I might add, no collateral damage which a drone or bomb would have inflicted.