Killing Oswald explores the mystery of how and why John F. Kennedy and Lee Harvey Oswald were assassinated in 1963, tracing Oswald's strange transformation from US Marine radar operator in Japan, monitoring U2 spy planes over Russia; to 20-year-old Marxist defector, decamping to Moscow threatening to share military secrets with the KGB; to pro-Castro activist in New Orleans and self-proclaimed patsy in Dallas. The film features interviews with authors John Newman, Dick Russell, David Kaiser and Joan Mellen, Cuban exile Antonio Veciana and Watergate burglar Eugenio Martinez; alongside rare archive film and audiotapes of Oswald and his alleged CIA handlers George de Mohrenschildt and David Atlee Phillips.