Jack Anderson had a Kennedy assassination book. Heard him on Art Bell, probably a year before Anderson died.
FWIW, according to Anderson, Castro was tired of the Brothers Kennedy trying to kill him, so he baited the mob with a "promise" of letting them have back all the casinos and such in Cuba if the mob would take care of the Castro's "problem".
Interesting take but it cannot explain the actions of the Intelligence agencies in covering it up.
JFK was exploring means of opening up to Castro and relations with Cuba so Castro had no motive in killing him and taking on such a huge risk. War and invasion of Cuba would result had any such plot been found out.