Documents released recently by the U.S. National Archives on President John F. Kennedy's assassination suggest the CIA was watching Lee Harvey Oswald much more closely than previously thought before the fatal shot was fired in Dallas, an author tells The Fifth Estate.

Former Washington Post reporter and author Jefferson Morley told The Fifth Estate the official story was that Oswald came out of nowhere and shot the president on Nov. 22, 1963.

"What the files show is that's a cover story. It's not true. High level CIA officials were paying attention to Oswald from 1959 to November 1963," said Morley, author of several books on the assassination, the CIA and a JFK website.

Author says CIA was paying close attention before JFK assassination 0:20

Morley said when Oswald travelled to Mexico City weeks before the assassination, his visit to the Soviet Embassy and the Cuban consulate were watched every step of the way, including his meeting with Valeriy Vladimirovich Kostikov, head of the KGB's Department 13, its assassination branch.

"Everywhere Oswald goes on this little adventure, he's tripping off CIA surveillance activity."

Morley said the CIA cover story was "our interest in Oswald was merely routine."

"Well, it wasn't routine. It was very intensive and at a very high level."

For more of the interview, watch "The JFK Files: The Murder of a President" on The Fifth Estate on CBC-TV Friday at 9 p.m.