Irma Dumke lived with her husband Paul, a hairdresser, in Hoppegarten near Berlin. During the war, she was obliged to work for a time in the village of Summt, north of Berlin. In 1943 she met a Jewish couple from Berlin there, Heinz and Grete Rosenbaum, who had gone underground with their young son Denny at the end of 1942. In October 1943 they were betrayed by an acquaintance. After hiding in Wilhelmshagen near Berlin, the Rosenbaums asked Irma Dumke for help in December 1943. She asked her neighbor Hildegard Linke whether the family could live in her garden house – without mentioning that they were Jews in hiding. During the day, the Rosenbaums spent most of the time in Irma Dumke’s home; she also provided the family with everything they needed.
From July 1944 the Rosenbaums hid in numerous different places, for safety reasons. They emigrated to New York in 1946, adopting the name of Rogers. The family kept in touch with Irma Gabriel, as she was called after her second marriage. In 1962 they suggested Irma Gabriel should be honored as an Unsung Heroine by the West Berlin senate.