I definitely agree that this is a hired gun.
If he was an insurgent then he would have shot civilians in order to spread panic like so many before him,but this guy only targets soldiers.
Iraqi or foreigner,it doesn't matter.What matter is that he's good and it will be a tough duel should the Army send a countersniper after him.
But I wonder,what the ranking were for the soldiers he killed.If he truly is the professional I think he is,then he would have gone for the highest ranking officer in the squad or group first,that's always been one of the major laws when it comes to sniping,always shoot the highest ranking soldier.