After Germany invaded Poland in 1939, he lived under the false name "Zuzga". Since 1942 he was a member of the National Military Organization in Łuków County, later he transferred to the National Armed Forces (NSZ). He finished his training in the NSZ training facility "Dym" (Smoke) in Jata, after which he conducted operations in Siedlce area. In May 1944 he became a leader of the regional command of NSZ in Węgrów. He was the top-ranked Polish Jewish officer in the Polish non-communist resistance.[3] On 1 June 1944 he was promoted to the rank of Major. One of his first actions as a leader was an attempt to negotiate joining forces with Home Army, an attempt which most likely failed. On 3 January 1945, he was arrested by the newly established (after the Soviet occupation of Poland), Communist secret police (Ministry of Public Security). He was later transferred to a prison in Otwock and tortured during questioning. After his Jewish origin was discovered, the Communists attempted to convince him to switch sides, an offer which he refused. He was executed on 4 February 1945.[5][7][8][9]
^HOLEWIŃSKI, WACŁAW (2015). HONOR MI NIE POZWALA [HONOR DOES NOT LET ME] (in Polish). ZYSK I S-KA. p. 328. ISBN978-83-7785-814-1. Stanisław Ostwind is an exceptional figure on the pages of Polish history. A Jew, a legionnaire, a policeman, a soldier ... of the National Armed Forces.
^Muszyński, Wojciech (2012). Nationalisms of different nations - book chapter by Wojciech Muszyński(PDF) (in Polish). Księgarnia Akademicka. p. 140. ISBN978-83-7638-132-9. The highest-ranking Jew in the structures of NSZ was Feliks Pisarewski "Parry" ... Another relatively high-ranking officer of Jewish origin in the NSZ hierarchy was Stanisław Ostwind vel Zuzga ps. "Kropidło"
^ abMariusz, Bechta (2009). Między Bolszewią a Niemcami. Konspiracja polityczna i wojskowa Polskiego Obozu Narodowego na Podlasiu w latach 1939-1952. Instytut Pamięci Narodowej. p. 519. ISBN978-83-73-99373-0.
^Nacjonalizmy różnych narodów perspektywa politologiczno-religioznawcza, Księgarnia Akademicka, book chapter by Wojciech Muszyński, page 140 in the PDF, ISBN978-83-7638-132-9, 2012, quote: "Pochodził z częściowo spolonizowanej rodziny żydowskiej z Warszawy, jako młody ochotnik wstąpił do I Brygady Legionów Polskich, uczestniczył jako podoficer w wojnie polsko-bolszewickiej. W okresie międzywojennym przyjął chrzest i pracował jako przodownik w Policji Państwowej." ("He came partly a Polonised Jewish family from Warsaw, as a young volunteer joined the First Brigade Polish Legions, he participated as a non-commissioned officer in the Polish-Bolshevik war. In the period He was baptized in the interwar period and worked as a leader in the State Police.)