According to the description in the book, one of these authors: Stefan Bałuk, Władysław Choma, Tadeusz Kinowski, Stanisław Kopf, Bolesław Malmurowicz, Stefan Józef Stryjniak, Dawid Szmulewski, Jerzy Tomaszewski, Ludwik Wajner · Public domain · via Wikimedia Commons
war crime
individual act constituting a serious violation of the laws of war