The father of Ingrid and Helga Gronowski was Walter Franz Gronowski, born on 8 January 1895 in Königsberg, Prussia (now Kaliningrad, Russia). Walter lived in May 1939 at Schönhauser Allee 51 in the Prenzlauer Berg district of Berlin, Germany. He was deported from Berlin on 6 March 1943 to Auschwitz Concentration Camp. He was further deported to Buchenwald Concentration Camp, where he died before the end of the war. The girls' mother was Erna Gronowski née Rosenthal. Her date and place of birth, as well as subsequent fate have not been determined, although according to Joods Monument contributor Aline Pennewaard, she died before war. (Amsterdam Archiefkaarten, German Federal Archives Memorial Book, Residents' List, and 1939 German Minority Census).
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