In 1987, Florentino Aspillaga, the most valuable Cuban intelligence officer ever to defect, provided the CIA with detailed information that Fidel Castro’s security forces knew and could have directed Lee Harvey Oswald’s plan to assassinate President Kennedy in Dallas. This potentially provocative news was buried among thousands of documents written on the tragic subject.

Now this vital piece of information has been made public as the main thesis of the book Castro’s Secrets: the CIA and Cuba’s Intelligence Machine, by Brian Latell, a historian and the CIA’s former National Intelligence Officer for Latin America. The book is a well researched and factual narrative that unmasks the official secrecy and ideologically driven theories that for many years have distorted the fundamental premises of the JFK assassination.

The son of a high-ranking communist official, Florentino Aspillaga was, in 1963, monitoring Miami radio communications from the CIA and Cuban exile operations working against Castro’s Cuba. This was his only assigned duty that year, until Nov. 22, around 9 a.m., when he was instructed to cancel the CIA radio monitoring and redirect his antennas to Texas. Aspillaga was ordered to immediately report on anything happening in that U.S. region. About four hours later, President Kennedy was assassinated in Dallas. Did Castro know that JFK would be killed?

As an expert analyst, Latell makes a cautious distinction between Castro’s advance knowledge and his direct involvement in the plot. But according to Jack Chiles, one of the CIA’s best agents who penetrated the inner circle of power in Moscow and Havana, Castro stated that Oswald came into the Cuban Embassy in Mexico and shouted, “I am going to kill Kennedy.” This event is well documented. From that moment on, the Cuban intelligence agents knew that Oswald was a fanatical and violent man that had a pathological hatred of JFK.

It is also well established that both John and Robert Kennedy were, at the time, engaged in the overthrow and demise of Castro. Fully committed to the task, Robert Kennedy oversaw the CIA clandestine missions to Cuba, not to be confused with “Operation Mongoose,” which was cancelled soon after the Missile Crisis. The plot to kill Castro was Robert Kennedy’s top priority and involved Rolando Cubela, a high-ranking Cuban revolutionary leader that, according to Latell, was a double agent that kept Fidel Castro informed of Kennedy’s assassination plots against him. It is worth noting that the Warren Commission was never made aware of the critical issue of the attempts against Castro’s life.

The profound dislike between Castro and the Kennedys was reciprocal. On Sept. 8, 1963 — 10 weeks before the Dallas tragedy — Castro spoke openly at a reception in the Brazilian Embassy, stating, “The United States’ leaders must realize that if they insist in their plan to eliminate Cuban leaders, they themselves will be in danger, we are prepared to fight them and answer in kind.”

Latell’s revelation that Cuban intelligence ordered Aspillaga to monitor information broadcasts from Texas, a few hours before Oswald’s assassination of the president, opens a new question about Cuba’s awareness of the criminal intent of a hot-headed fanatic that could have been manipulated by Cuban agents and encouraged to fulfill his plan. Oswald’s brother said that Lee Harvey was easily influenced and that someone had to put him up to the plan — a possible scenario.

The ideologically driven conspiracy theory, including Oliver Stone’s fictional film on JFK’s murder, had discarded the idea that Castro was behind the assassination, yet Latell’s superbly researched book offers vital information establishing that Cuba’s intelligence service had advanced knowledge of Oswald’s criminal intent and Castro’s awareness, through Rolando Cubela, of the Kennedy brothers’ plot on Castro’s life.

Former President Lyndon Johnson is among several high-ranking U.S. officials who believed in Cuba’s involvement in JFK’s assassination. In a TV interview with Howard K. Smith, Johnson said, “Well, Kennedy tried to get Fidel Castro, but Fidel Castro got Kennedy first.” On this issue, with the testimony of Florentino Aspillaga, Latell’s book opens new and startling evidence about the Dallas tragedy.

Pedro Roig, former director of the Office of Cuba Broadcasting for Radio and TV Marti, is a senior research associate at the Institute for Cuban and Cuban American Studies, University of Miami.