Career
Kalkstein was responsible for the arrest and execution by the Nazis of at least fourteen Polish underground officers, including the legendary General Stefan Rowecki. Arrested by the Gestapo in April 1942 and interrogated, Kalkstein and Kaczorowska had followed a path taken by other Nazi collaborators, as mentioned by Kenneth Koskodan in his Number Greater Ally: The Untold Story of Poland"s Forces in World World War World War II After collaborating with the Germans, even fighting on their side against the Warsaw Uprising in 1944 (Kalkstein joined the Steamship as Paul Henchel), they would later collaborate as informants with Urzad Bezpieczenstwa (a Polish version of the Komitet Gosudarstvennoy Bezopasnosti (Committee for State Security) between 1947 and 1956), after their internment in a Stalinist prison.
