But this does go back to psychology. He may have believed at the time that he saw the guy point the rifle at someone and even load it (which is possible if the guy didn't know what kind of gun it was since certain movements can appear to be loading it when it comes to perspective). When is something a lie? Is a statement a lie when it is something a person knows is wrong or when what they believe is proven wrong?
Now, maybe this guy did truly lie on purpose, and if proven, he should be held accountable. However, this does not prove any lie on his part, only a change in perspective, especially since he had since been shown the video and people adjust their perspectives to new facts and information, even subconsciously.