By 1963, Cuban exiles bitterly opposed to Castro were frustrated by the Kennedy administration. Many of them had come to conclude that the U.S. President was an obstacle requiring elimination even more urgently than the Cuban dictator. When it became known to anti-Castro Cuban exiles that Kennedy had agreed to stop the raids on Cuba, the exiles considered the Kennedy-Khrushchev deal anything but a victory. To them, it was another betrayal.
There is evidence that by the fall of 1963, informal overtures for better United States-Cuban relations had been authorized by President Kennedy. Talks between United States and Cuban officials at the United Nations were under consideration. In addition, the United States had attempted in the period after the missile crisis to stem the anti-Castro raids by, at least publicly, refusing to sanction them. But covert action by the United States had neither ceased nor escaped Castro's notice, and the rhetoric indicated that the crisis could explode anew at any time.
The Select Committee on Assassinations of the U.S. House of Representatives found in 1979 that the CIA-Mafia-Cuban plots had all the elements necessary for a successful assassination conspiracy -- people, motive and means, and the evidence indicated that the participants might well have considered using the resources at their disposal to increase their power and alleviate their problems by assassinating the President. Anti-Castro Cuban groups and individual activists had the motive, based on what they considered President Kennedy's betrayal of their cause, the liberation of Cuba from the Castro regime; and the means, since they were trained and practiced in violent acts, the result of the guerrilla warfare they were waging against Castro. Certain associations of Lee Harvey Oswald were or may have been with anti-Castro activists.
The Select Committee on Assassinations found in its investigation that organized crime probably was active in attempts to assassinate Castro, independent of any activity it engaged in with the CIA, as the 1977 Task Force Report had suggested. The allegation that President Kennedy was killed as a result of a Mafia-CIA plot that was turned around by Castro was passed to Drew Pearson and Jack Anderson. By late 1962 and 1963, underworld leaders had been given sufficient reason by the organized crime program of the Department of Justice to eliminate President Kennedy.