Searched: "world war ii stockade army", "world war ii court martial murder", "articles of war", and tons of other stuff that did not help. Oh, and I almost tried "U.S. army war crime", but I was not up to dealing with the inevitable results.
Protagonist, an American soldier, is alone off-duty when he comes upon a fugitive Japanese warrant officer exchanging weapons and food with local collaborator family. Enemy is subject of standing orders to be captured or killed for war crimes towards civilian prisoners earlier in the war. Enemy is also subject of personal and obsessive enmity from protagonist. Enemy fires first at protagonist. Protagonist fires back. Collaborators (father and son) fire at him, are killed. Female relative of collaborators (mother) attacks protagonist with large machete, is killed. Unknown to protagonist, enemy has taken juvenile hostage (daughter). Protagonist, in possibly the worst choice of his life, comes out shooting, killing both enemy and hostage.
Details: at this point a state of war still existed; collaboration is considered a death penalty crime by local government restored to power; protagonist was not on a mission (was moving from one outpost to another in the area).
Question: what will he be charged with, if anything, under the Articles of War? Is a murder charge (and the firing squad if guilty) a real possibility? What punishment will he receive from the military justice system? I already assume, if he lives, dishonorable discharge and loss of all honors and benefits.
Edit: Is there such a thing as a military beta for combat sequences? I have done my best to reconstruct historical attacks/battles from available data, but not having any real military experience, my squad- and patrol-sized "fight scenes" are pure guesswork (based on "respectable" movies and TV shows and just thinking Now How Would I Do This If I Were Him, that Tree is Over There, this Ditch is Here, and They're Looking Thatway? You know, playground tactics.) I ask because I'm editing one scene now and I just muttered "Aragorn" and that was not a professional sign.