I wonder if there weren't TWO shooters present that day who weren't in any way involved with one another or even aware of one another’s presence. There is pretty good enhanced photographic evidence (BBC'S ‘The Men Who Killed The Kennedys’’) that another shooter was behind a fence (on the knoll?) Between the two (Oswald and Anonymous) they may have represented some combination of lone nut/Castro/Mob. This would cut the number of people actually in on the plans down to a very small number, all the while creating confusing evidence that naturally hinted at some kind of Big Plot. I have always had trouble believing any conspiracy involving a lot of people would have been kept quiet.
There is no photographic evidence of a second shooter. "The Men Who Killed Kennedy" is a joke. Worse than a Michael Moore movie. Even the rational and well-informed conspiracists know it is garbage.