The Jack Ruby episode is a perfect example of why so many conspiracy theories came about after the John F. Kennedy assassination. Because first an American president is assassinated and then the assassin, or at least accused assassin is shot and killed as well. And left many Americans to believe that this is too unreal and can't be natural acts. And that something is up that would explain these crazy activities from happening like forces in the Federal Government working to see that Jack Kennedy and Lee Oswald are killed. Because they saw Jack Kennedy as a threat and that Lee Oswald knew too much about not only the assassination itself, but the all of the powers associated with the JFK assassination. And didn't want their power and control to be threatened.
We'll never know the full story of what Jack Ruby knew about this case, because he died three years after the JFK assassination. And we might already know everything that he knows about this case. But Jack Ruby and his associations with organized crime figures in Dallas and the hatred that the Italian Mafia had for President Kennedy and his administration leave a lot people wondering if they put Ruby up to killing the President, because they didn't want Oswald to talk. The only conspiracy theory that has any credibility whatsoever that leaves intelligent sane people like Robert Blakey who worked for the House Assassinations Committee wondering if someone other than Lee Oswald was involved in the JFK assassination is the possible organized crime connection.