Max and Ida Cohn were married on 8 August 1912 in Magdeburg-Neustadt. In 1913, the couple relocated to Hombruch, where the first son, Heinz Cohn, was born on 14 April 1914. At the time when daughter Johanna Sofie was born, the family were living at Bahnhofstr. 20 in Hombruch. In the address directory of the parish of Kirchhörde, the address appears in 1922 as Bahnhofstr. 26, but after the integration of Hombruch into Greater Dortmund, this was changed into Harkortstrasse 26. From Hombruch, the family moved in 1933 to Münsterstrasse 96 (today: No. 106), where father Max carried on a manufactured goods business.

In 1941, the parents were forced to move to the collective accommodation at Parsevalstrasse in Huckarde; here, Max Cohn died on 8 December 1941 following a stroke.
Ida Cohn was deported as part of Transport X/1 to Theresienstadt on 29 July 1942. She stayed there only around 8 weeks, and was then assigned to Transport Bq, destined for Treblinka. There, she was most probably murdered immediately or soon after her arrival.

The Cohns’ son Heinz deregistered from his home address on 12 May 1939 in order to move to Gut Winkel near Spreenhagen. Gut Winkel had been a recognized Hakhshara establishment since 1934. Here, young Jews of both sexes were able to receive training at an agricultural training facility in preparation for emigration to Palestine/Israel. At the start of 1941, the Nazis either closed down the Hakhshara establishments or turned them into forced labour camps.
Heinz Cohn, together with his wife Elli, née Stern, and their joint daughter Mathel Cohn (born 6.12.1942, Berlin), was deported on 19 April 1942 from Berlin to Auschwitz, where they were presumably murdered immediately after their arrival.

Sofie Johanna Cohn deregistered and left for England on 3 August 1939, just before outbreak of the war. She married in England, and later bore the surname Reissner. In the late 1950s/early 1960s, she successfully filed compensation claims for herself, her parents and her brother.