Democratic presidential candidate Robert Kennedy Jr. said the Central Intelligence Agency is responsible “beyond a reasonable doubt” for the assassination of his uncle, President John F. Kennedy.

“There is overwhelming evidence that the CIA was involved in his murder. I think it’s beyond a reasonable doubt at this point,” Kennedy said about his uncle’s 1963 assassination in Dallas, Texas, during a radio interview Sunday. “The evidence is overwhelming that the CIA was involved in the murder, and in the cover-up,” he also said.

Kennedy also recommended a book by James Douglas, “JFK and the Unspeakable,” to learn more about the topic.

Kennedy, who was 14 when his father Robert Kennedy was assassinated during his 1968 presidential campaign, nevertheless acknowledge about his claim: “The evidence of the CIA [being] involved in my father’s death is very convincing but it’s circumstantial.”

The Warren Commission, the official congressional probe into John F. Kennedy’s death, concluded in 1964 that Lee Harvey Oswald acted alone in assassinating the president. However, the House Select Committee on Assassinations concluded in 1979 that Kennedy was “probably assassinated as a result of a conspiracy,” but said the FBI, CIA and Secret Service were not involved in the plot.