I fully believe the evidence overwhelming supports the Mafia connection, although not over a girlfriend. Even back then, women weren't that important to the mob.
Old Joe Kennedy had gotten in bed with the Mafia to stuff the ballot boxes in Chicago and distribute cash through West Virginia. The payoff was to be the Kennedy administration laying off the mob.
Well it all worked out. The ‘extra’ votes in Chicago carried the day, and Kennedy won the electoral vote. Of course as soon as he was elected, he appointed his brother Attorney General, who immediately announced he was focusing on the mob.
This was the ‘old’ mob, the so called ‘men of honor’ guys who believed no transgression was to be left unpunished. Old Joe by then had suffered a stroke, so he wouldn't have known if he was alive or dead anyway. But there is some very incriminating tape the FBI recorded of Mafia bosses. One of their discussions includes, “if you can't hurt the guy anymore, you take away what he wanted.” Something like five months later JFK was dead.
Oops, I should have read the rest of the posts before I posted. I agree with you about the mafia.