An estimated 320,000 documents regarding President John F. Kennedy's assassination have been reviewed, according to the National Archives and Records Administration. But a June 22, 1962 memo from a CIA employee about an operation to read the mail of Lee Harvey Oswald remained a mystery until its recent de-classification. NewsNation correspondent Evan Lambert joins the special report “Unsolved: The JFK Assassination” with the story, as new details come to light about JFK's killing.