After his brother was shot dead in Dallas on Nov. 22 1963, the Attorney General suspected the CIA, the Mafia and anti-Castro Cubans, according to an excellent article in the The Boston Globe.
Interestingly, Bobby never for moment considered the now-fashionable “Castro did it” theory.
(If the link hits a paywall, click here for the story)
The chief suspects, according to reporters Bryan Bender and Neil Swidey:
After hearing the news from Dallas, “Bobby picked up the phone and dialed a Chicago lawyer for the National Labor Relations Board by the name of Julius Draznin. Bobby knew Draznin had impeccable mob sources, so he asked him to do some digging to determine if there had been any Mafia involvement in the assassination. ‘I called him back in a couple of days,'” Draznin later told Evan Thomas, author of ‘Robert Kennedy: His Life.’ ‘There was nothing.'”
“When [Director John] McCone arrived from CIA headquarters, Bobby paced the lawn of his estate with him. As Bobby later told historian and aide Arthur Schlesinger, he asked McCone point blank if the CIA ‘had killed my brother, and I asked him in a way that he couldn’t lie to me, and they hadn’t.’ McCone was a devout Catholic, leading many to believe that their shared faith was behind Bobby’s confidence in the CIA director’s candor. McCone, according to Schlesinger’s biography, ‘Robert Kennedy and His Times,’ would come to believe that there had been two shooters in Dallas, though he didn’t think the American intelligence agency was in any way involved.
“But McCone almost certainly didn’t know the whole truth ….”
“In the time that Bobby had been overseeing his brother’s so-called Special Group team on Cuba, he had come to appreciate just how ungovernable the Cuban exile community could be. It hadn’t taken long on Nov. 22 for speculation to focus on the possible involvement of Fidel Castro, given the Kennedy administration’s repeated attempts to oust or assassinate the Communist leader. That speculation only intensified after the arrest of Lee Harvey Oswald, whose record of pro-Castro agitation quickly came to light. Yet it’s intriguing that Bobby’s suspicion of possible Cuban involvement seemed to focus squarely on the anti-Castro crowd.”