Johann Wenzel was a German Communist, highly professional GRU agent and radio operator of the espionage group that was later called the Red Orchestra by the Abwehr in Belgium and the Netherlands. His aliases were Professor, Charles, Bergmann, Hans, and Hermann. Wenzel was most notable as the person who exposed the Red Orchestra after his transmissions were discovered by the Funkabwehr, later leading to his capture by the Gestapo on 29–30 June 1942.