If you really want the information, it is available in the book "Ultimate Sacrifice" by Lamar Waldron and Thom Hartmann. They did a ten year study. It's a fascinating book and plausible. Kennedy was killed by Marcello crime syndicate which included Jack Ruby. Trafficante tried in Miami but was unsuccessful and Johnny Roselli tried in Chicago but no dice. The mafia and the CIA had a plan to overthrow Castro by killing him and placing someone else in his spot. The mafia was enlisted to effect this but decided on killing JFK instead as a revenge for Bobby's probe of organized crime. The idea was to, in Marcello's words, "to cut off the head of the serpent".

I wouldn't trust anything that E. Howard Hunt has to say.

Frank