Wasicky joined the NSDAP and the SS (he had the rank of SS-Sturmbannführer). From 1941 to 1944, he worked in the concentration-camp Mauthausen. He was in charge of choosing victims to be killed, and of poisoning them with the gas Zyklon-B. He also drove trucks that were used for killing people by exhaust gas. Up to 15,000 people had been killed at Mauthausen as well as neighboring Hartheim.