In December 1945 and January 1946 the four Military Governments ordered German authorities to support the tracing bureaus in their pertinent zones. The authorities had to carry out investigations on foreigners, who had been staying in the administrative districts since September 1939, be it for a short time or permanently, be it voluntarily or involuntarily. The authorities also had to report the whereabouts of German Jews. The information compiled as a result of this order was listed by specific categories. More than two million of these lists are kept at the ITS.