Margarete Liebert was born into a Jewish family in Sondershausen on October 9, 1895. She moved to Berlin and married the merchant Ernst Koopmann, for him it was the second marriage. He had a daughter Renate from his first marriage, who was born in Berlin on July 23, 1931. Ernst and Margarete Koopmann then moved after 1938 to a relative of Margarete Koopmann, the widowed Jenny Liebert, at Beckerstrasse 5 in Schöneberg.

Ernst Koopmann was born into a Jewish family in Bremen on February 14, 1902. He became a merchant, moved to Berlin and married Betty Scharlinski, who was born in Berlin on August 25, 1905. Their daughter Renate was born on July 23, 1931.

Johanna Lewin was born in Beelitz on April 14, 1902, the daughter of Selig Lewin and his wife Therese.