The massacres in Piaśnica were a set of mass executions carried out by Nazi Germany during World War II , between the fall of 1939 and spring of 1940 in Piaśnica Wielka ( Groß Piasnitz ) in the Darzlubska Wilderness near Wejherowo . The exact number of people murdered is unknown , but estimates range between 12,000 and 14,000 victims . Most of them were Polish intellectuals from Gdańsk Pomerania , but Poles , Jews , Czechs and German inmates from mental hospitals from General Government and the Third Reich were also murdered . After the Stutthof concentration camp , Piaśnica was the largest site of killings of Polish civilians in Pomerania by the Germans , and for this reason is sometimes referred to as the " second " or " Pomeranian " Katyn . It was the first large scale Nazi atrocity in occupied Poland
Katyn
Katyn massacre
Massacres in Piaśnica