Did the sniper take some shots to get his ranging? Seems that he would have had to take one or two. If not, that was the most phenomenal single shot kill ever.
Does it count if he was firing into a group and happened to hit a target, but not necessarily the specific person that he was aiming at initially?
He probably had multiple ways to confirm his range. If he couldn't range with a laser range finder (that a long way, but I am guessing someone makes one that reaches out that far, an expensive one no doubt), then he could look at a map of the city and figure his range to where he was observing the target.
Would not think he would want to fire for finding range, as that would likely make the gophers go to ground. But there was a video a few months back of the idiots in Syria dancing around and firing in to the air while a sniper was taking shots, and one of them celebrated "for the rest of his life" if you know what I mean.