If he murders a civilian as part of a military sponsored program of ethnic cleansing (genocide), I would say yes.
If he kills an enemy soldier who is trying to kill him, and whose army is engaged in aggression, almost certainly not.
What about killing civilians as part of a program to destroy the enemy’s ability to fight (e.g. bombing enemy cities as was done in World War II)? What about killing an enemy soldier when the enemy country can rightly claim to be defending itself from a rodef (i.e. our soldier’s country)? What about a soldier ordered to destroy property as retaliation or engage in sexual attacks on enemy civilians?