On September 19, 1940, he deliberately went out during a Warsaw street roundup (łapanka), and was caught by the Germans along with some 2,000 innocent civilians (among them, Władysław Bartoszewski).[9] After two days of torture in Wehrmacht barracks, he was sent to Auschwitz. Pilecki was tattooed on his forearm with the number 4859.[9]
Auschwitz concentration camp photos of Pilecki (1941)
At Auschwitz, while working in various kommandos and surviving pneumonia, Pilecki organized an underground Union of Military Organizations (Związek Organizacji Wojskowej, ZOW).[3][10] Many smaller underground organizations at Auschwitz eventually merged with ZOW.[3][11] ZOW's tasks were to improve inmate morale, provide news from outside, distribute extra food and clothing to members, set up intelligence networks, and train detachments to take over the camp in the event of a relief attack by the Home Army, arms airdrops, or an airborne landing by the Polish 1st Independent Parachute Brigade, based in Britain.[3][10]
ZOW provided the Polish underground with priceless information on the camp.[10] From October 1940, ZOW sent reports to Warsaw,[12] and beginning March 1941, Pilecki's reports were being forwarded via the Polish resistance to the British government in London.[13] These reports were a principal source of intelligence on Auschwitz for the Western Allies. Pilecki hoped that either the Allies would drop arms or troops into the camp, or the Home Army would organize an assault on it from outside. Such plans, however, were all judged impossible to carry out.[3][11] Meanwhile the Gestapo redoubled its efforts to ferret out ZOW members, succeeding in killing many of them.[3][14] Pilecki decided to break out of the camp, with the hope of personally convincing Home Army leaders that a rescue attempt was a valid option. When he was assigned to a night shift at a camp bakery outside the fence, he and two comrades overpowered a guard, cut the phone line and escaped on the night of April 26/27, 1943, taking along documents stolen from the Germans.