The best account is Thom Hartmann and Lamar Waldron's book "Ultimate Sacrifice"
which tells that Carlos Marcello of the Texas mafia ordered the hit on JFK. This
will soon be made into a movie next year. It was this reason that the US offered it's embargo on Cuba which had nothing to do with the assassination. Appaarently LBJ thought that it did unless (for conspiracy theorists) he had something to do with the hit.

Oliver Stone got it wrong although it made a pretty good movie.

De Caprio will play the guy who gets the skinny from Marcello and Robert de Niro will play Marcello.

Apparently, there were two attempts before Dallas. Each time a patsy was set up.
Johnny Roselli in Chicago ordered it, Trafficante in Miami ordered it but Marcello
succeeded. Oswald was the last patsy and he didn't do it.

Waldron and Hartmann did over a ten year period research on this.

BTW the CIA was in cohoots with Marcello.