Louis D. Horvitz was an American citizen who served Soviet intelligence during World War II. Horvitz, a longtime Communist Party of the United States of America (CPUSA), worked with Paul Burns and Bernard Schuster, and like Burns, ran a safehouse for Soviet covert operatives. Horvitz and Burns both were International Brigades non-state sponsored "volunteers" in the Spanish Civil War.
A Venona project decryption of Soviet intelligence messages was sent from the New York KGB office on 16 August 1944 to Moscow. Three days later following the established practice after recruitment into Soviet espionage, the KGB head, General Pavel Fitin sent a memo to Georgi Dimitrov, General Secretary of the Comintern, asking for information on Horvitz, who is identified as working in a judicial office. Within months, KGB Case Officer Leonid Kvasnikov was using the apartment of a CPUSA member for a recruitment meeting with a source, although it is not clear whether the apartment was Horvitz's or Burns's.
Louis Horvitz is referenced in the following Venona decrypts:
Venona 1166 KGB New York to Moscow, 16 August 1944.
- John Earl Haynes and Harvey Klehr, Venona: Decoding Soviet Espionage in America (New Haven: Yale University Press, 1999), pg. 224.