The circumstances of Kaczmarz 's death are unclear . In early September 1939 , he was called up for military service by the Russian-controlled part of partitioned Poland , and was not heard from afterwards . Theories for his death include the possibility that he died a few days later near Nisko ( the source of his last letter to his wife ) in a German bombing raid on a train he was traveling in , that he died later that month in combat against the Germans near Umiastów , or that he was murdered by the NKVD in April or May 1940 as part of the Katyń massacre
Katyń massacre
Katyn massacre
Stefan Kaczmarz