The Cuban intelligence service, under the leadership of Fidel Castro, connived in the assassination of President John F. Kennedy, according to a new book by a retired CIA analyst. Coming from Brian Latell, the Agency’s former national intelligence officer for Latin America, the charge is both sensational and uncorroborated, yet still important.

Latell says flatly that Castro played a role in Kennedy’s murder in Dallas on Nov. 22, 1963.

“Castro and a small number of Cuban intelligence officers were complicit in Kennedy’s death but … their involvement fell short of an organized assassination plot,” he writes in “Castro’s Secrets: The CIA and Cuba’s Intelligence Machine,” a well-footnoted polemic about Cuba’s General Directorate of Intelligence to be published next month. Latell says accused assassin Lee Harvey Oswald told Cuban diplomats in Mexico City in September 1963 that he might kill JFK. Latell also speculates, without any direct evidence, that Oswald kept the Cubans apprised of his plans as he made his way to Dallas.

The  charge is sensational because Latell is the highest-ranking former CIA official to ever accuse the Cuban leader of personal responsibility for JFK’s death. It is uncorroborated because much of the evidence Latell cites in the book is not in the public record or available to JFK scholars. Even the CIA is keeping its distance. When I asked the Agency to comment on Latell’s thesis on Wednesday, a spokesperson replied, “You can report the CIA declined comment.”...