Milton Schwartz was an American who worked for Soviet Military Intelligence GRU during World War II. A 1943 message, later decrypted by the Army Signals Intelligence Corp, revealed Schwartz's activity on behalf of the GRU to be of such value that a request was put in for $1200 to assist Schwartz in personal financial matters.
Schwartz's code name with the GRU, and deciphered by the Venona project is "Matvey".
References
- Who was 'Venona's' 'Ales'? cryptanalysis and the Hiss case Intelligence & National Security, Taylor & Francis Group, Volume 18, Number 3 / September 2003, pgs. 45 - 72
- John Earl Haynes and Harvey Klehr, Venona: Decoding Soviet Espionage in America, Yale University Press (1999), pgs. 186, 364, 462.