After the German invasion of Poland , both Roman and his father acquired German citizenship in order to avoid expulsion by the Nazis to the General Government and to provide cover for espionage activities on part of the Polish resistance . Roman was drafted into the Wehrmacht and stationed on the island of Uznam , as a communications specialist . Träger was fairly unrestrained in his movements around the island , including in the factory and testing site of the V-1 and V-2 rockets , and soon began making sketches of the layout of various key structures
expulsion by the Nazis
Expulsion of Poles by Nazi Germany
Roman Träger