Hanna Blumenfeld, Hermann's niece, daughter of his twin sister was born on the 19th of February 1924 in Bad Mergentheim. Hanna was murdered, at the age of 17, together with her father, Rudolf Blumenfeld and mother, Rosa (Fechenbach) Blumenfeld at the Lithuanian death camp Fort IX near Kaunas (Kowno) on 25th November 1941.