In September 1939 after the German invasion of Poland, and the subsequent Soviet invasion of Poland he found himself in the Soviet occupied zone. On 29 September he was arrested by the NKVD. In July 1941 he was sentenced to death by the Soviet authorities, although the sentence was later commuted to ten years in the Gulag. After the Nazi invasion of Soviet Union, and the signing of the Sikorski–Mayski Agreement between the Polish Government in Exile and the Soviet Union he was released from the gulag.