I think Bobby and JFK pissed off the mob and they did him in. Bobby went back on his word with the mob. That is a no no. Or maybe it was LBJ? LOL
Joe Kennedy had solicited the assistance of the mob to sway some unions to help in the 1960 election. Included was the dem primary in WV in which JFK upset Humphrey and the city of Chicago, which reportedly held back vote tallies to see how many votes JFK needed to beat Nixon.
After the boys got in and went after the teamsters and the mob, Giancano sent Roselli and another guy to Hyannisport to remind the old man that the organization had helped JFK get elected. Joe said he would talk to them when the family got together at Christmas. Before that the old man had a major stroke and the conversation did not happen.
The problem with the JFK assassination is there's plenty of motive and capability to go around. Hard evidence is another thing all together.
But at this point, I think who ever was involved is pushing up daisies now.