Mordecai, known in Yiddish as Motl, was born to a religious Jewish family with six children. His hometown of Kozienice, located near a birch forest, had an important lumber industry. After graduating from secondary school, Mordecai entered the lumber business. His small, successful company bought and sold lumber.
1933-39: A few months after the Germans invaded Poland in September 1939, Mordecai's father was warned to leave because, as a prominent member of the community, it was likely that the Germans would arrest him. Mordecai fled with his father, sister, brother-in-law, and girlfriend for Soviet-occupied Poland, where they hoped to find refuge. On the way, Mordecai married his girlfriend.
1940-41: After being safely smuggled across the border between Soviet- and German-occupied parts of Poland, Mordecai worked for the Soviet-controlled lumber industry near Lvov until 1941, when the Germans invaded western Ukraine. With the invasion, Nazi mobile killing units (Einsatzgruppen) began to murder tens of thousands of Jews in that region.
Thirty-three-year-old Mordecai and his family were not heard from again. They may have been among the thousands of Jews killed by the Einsatzgruppen.