Even during peace time, sadly, some in our military have engaged in crimes, such as rape and murder. They HAVE been prosecuted for it and just because you don't know about such things, doesn't mean that that is not so.
Instead of posting from your feelings, go do some research and post with knowledge.
I take it you consider engaging the enemy which results in murder as a crime and our troops should be charged for murder. Well, that's where you and I disagree.