Behenna appears to be responsible for initiating events that ultimately resulted in the need for him to have to defend himself, but to say he just executed this guy is making an unsubstantiated charge and that's why there's an appeal to his sentence.
Fyscat, why do you assert that Behenna took this Iraqi terrorist to a ditch to execute him?
You may not know this, but when you threaten someone with a gun, you better be prepared to use it and for the fall out that follows. Specifically when your in the middle of nowhere and making it look like the other person is gonna die unless you get want you want.