[user104658]

He could have refused and then he would probably have been shot.

I'm not going to pass too much comment because I don't know the ins and outs of this specific case (maybe he went above and beyond the call of duty), but in general, my opinion is that the only people who should be considered guilty of war crimes are those giving the orders, not those following them.

Otherwise every soldier that is or ever has been to war is a criminal.