Fidel Castro Killed JFK? Top Government Official Had 'Feeling in His Guts' That Cuba Paid Off Oswald

President John F. Kennedy in an undated photograph courtesy of the John F. Kennedy Presidential Library and Museum. REUTERS/JFK PRESIDENTIAL LIBRARY AND MUSEUM

At least one top U.S. official was convinced former Cuban dictator Fidel Castro orchestrated the assassination of President John F. Kennedy, according to the latest trove of declassified documents released Friday by the National Archives and Records Administration related to Kennedy's death.

Assistant Secretary of State for Inter-American Affairs and later U.S. Ambassador to Mexico, Thomas C. Mann said he had a "feeling in his guts" that Castro paid Lee Harvey Oswald to assassinate the 35th president on November 22, 1963, in Dallas, Texas, according to declassified CIA documents.

Mann turned over his unsubstantiated claims in the form of a file to the President's Commission on the Assassination of President Kennedy, the previously top-secret documents state.

President John F. Kennedy, first lady Jaqueline Kennedy and Texas Governor John Connally ride in a limousine moments before Kennedy was assassinated in Dallas, Texas, on November 22, 1963. File Photo via REUTERS

"The file turned over to the Commission by Ambassador Mann contains statements of opinion by him that Oswald was probably involved in a sinister fashion, especially by way of taking a bribe, with the Cuban Embassy in Mexico City or with some other Castro agency," the documents state.

Mann's suspicions were reinforced because Oswald was allegedly seen taking $6,500 in American currency ($51,621 if adjusted to today's buying power) from an individual at the Cuban Embassy in Mexico City. They were further reinforced when Oswald was seen frequently at a Mexican hotel known in intelligence circles as a headquarters for pro-Castro activities.

No evidence to date has materialized to validate Mann's belief.

Cuban President Fidel Castro waves to journalists upon his arrival at Asuncion airport, on August 14, 2003. Castro arrived there to attend the swearing in of Nicanor Duarte Frutos as Paraguay's next president. MARIO VALDEZ/REUTERS

Mann believed Castro, who died last year at age 90 of an undisclosed cause, had the character to carry out the "ruthless" killing, he said.

"Castro was the kind of dictator who might have carried out this kind of ruthless action, either through some hope of gaining from it or simply as revenge," the documents state.

The U.S. was embroiled in a political and military standoff in October 1962 over the installation of nuclear-armed Soviet missiles in Cuba—known as the Cuban Missile Crisis. Kennedy was assassinated the next year.

Cuban President Fidel Castro speaks before a crowd of 10,000 people, on October 26, 2002, in Matanzas province. Castro was lauding Hurricane Michelle recovery efforts. REUTERS

The latest batch of more than 600 documents in the once-secret files was initially withheld from the initial release because of national security concerns. Friday's release follows last week's release of the first batch of 2,800 documents.

While the documents contain conspiracy theories, the official narrative has remained unchanged. Oswald, a troubled former Marine and one-time defector to the Soviet Union, fired three bullets when Kennedy's motorcade passed by the Texas School Book Depository. The bullets hit Kennedy's neck and head, and he died the same day in the emergency room of Parkland Memorial Hospital.

Thousands of additional documents will "ultimately be released," the CIA said.