The whole thing was one big whitewash. If this had happened today, it would have been exposed much quicker and easier. Unfortunately, social media didn't exist back then, every city in the land had three - at most - TV stations, and of course newspapers. That was it. So it was very easy for Hoover to set up the marching orders and have it flow downward that "...Oswald did it and he had no confederates." And because the media back then could be massaged by the government to do its bidding, it continued on that way until Stone surprised them with his film. Then, we saw the media doing it all over again - a redux if you will - by passing on the same tireless, corrupt and inaccurate storyline.
That's why other parts of the world never bought into the hogwash that the WC came up with.
It was a sham, pure and simple.