Concentration camp prisoners were not the only people who were used to construct fighter planes for Messerschmitt. From 1942, many Soviet forced laborers also had to work for the company. They were referred to as Ostarbeiter (“Eastern workers”) and they wore an OST tag sewn onto their clothing. Their labor cards can be identified by the Einsatz-Ost stamp in the space where the person’s nationality would be noted on other cards. There are also cards for Western European forced laborers and for prisoners of war who had to work for Messerschmitt. When the cards were no longer needed, Messerschmitt employees crossed out the information on the front and used the back to record information about a concentration camp prisoner. It is only by chance, therefore, that information about these forced laborers reached the ITS.