I have an issue with your use of "murder", which implies illegality in the killing. Killing in war, "sanctioned", is NOT murder.

Also, war is about more than killing- it is the application of violence to achieve political ends, but the goal is not about killing. If there was a way to impose political will through violence WITHOUT killing, I think that it would still be war.

Grossman's work may have some good input. The research that supported the TrainFire or QuickFire marksmanship training (mid-60s?) may be useful. This is the system that started using humanoid pop-up targets.