Considering the leftist source, I doubt the validity of the whole story. That being said, if the is/was ever such a sniper, my money is on a hired foreign gun. As Kilgore said, the "insurgents" aren't noted for their proficiency or professionalism.
I hate newspapermen. They come into camp and pick up their camp rumors and print them as facts. I regard them as spies, which in truth, they are.
Gen. W.T. Sherman