 Wenzel decided to collaborate after he was tortured.It was his exposure of the radio codes that enabled Referat 12, the cipher bureaux of the Funkabwehr, to decipher Red Orchestra message traffic.The unit had been tracking Red Orchestra radio transmissions since June 1941 and in December 1941 had raided a house in Brussels where Wenzel was transmitting, that was found to contain a large number of coded messages.