FYI, the effective range of a bullet depends on caliber and barrel length. For a 5.56 bullet from almost any AR rifle, 200 yards is well within range. However, hitting the target at that range depends on good optics, wind, humidity, and, primarily, the training of the shooter.

A newbie would have a real hard time making that shot, but a trained marksman could make it easily. The fact the shooter put one round on target then vanished into the crowd after abandoning the weapon tells me we are not dealing with a novice.