Lee Harvey Oswald defected to the Soviet Union in September 1959, married Soviet citizen Marina Prusakova, and returned to the United States in June 1962. His documented contacts with Soviet and Cuban officials — including a visit to the Soviet embassy in Mexico City weeks before the assassination — have fuelled claims that Oswald was a KGB asset and that the Soviet Union ordered the assassination of President Kennedy. Declassified CIA, FBI, and post-Soviet KGB records confirm Oswald's presence in the USSR and his Soviet contacts; they do not support the "Soviet-ordered hit" conclusion, which remains unsubstantiated.