Gus G. Russo (born 1950 in Baltimore, Maryland) is an American author and researcher of the assassination of John F. Kennedy. Russo was part of a team of researchers that worked on the 1993 Frontline Lee Harvey Oswald documentary, Who Was Lee Harvey Oswald?, for PBS. He is the author of Live by the Sword: The Secret War Against Castro and the Death of JFK, a book which states that Lee Harvey Oswald alone killed the president in retribution for Kennedy's policies toward Fidel Castro and Cuba.