Leopold Haase died in Germany almost a decade after his retirement, in 1917. His son Hugo continued the family's fur shop, but eventually was caught up in the Russian revolution. His property was confiscated, and he eventually made his way to Germany at some point in the 1920s. Leopold's widow, Clara, ended up in Stuttgart and faced destitution in the aftermath of World War I.
In a letter sent to Helene Haase Mueller, the daughter of Charles Haase, Clara lamented that "Now I sell one piece after another and discover each time anew, with tears, that you can't make a lasting agreement with the forces of destiny."
The two branches of the Haase family apparently lost contact with each other after this communication, but sixty years later, in 1985, Leopold's grandson Helmut Haase met Mary Geschwind, Charles Haase's great-great-granddaughter, and the distant cousins were able to share documents each had collected and fill in gaps in their shared family history.