"In 1940, Pilecki presented to his superiors a plan to enter Germany's Auschwitz concentration camp at Oświęcim (the Polish name of the locality), gather intelligence on the camp from the inside, and organize inmate resistance. Until then, little had been known about the Germans' running of the camp and it was thought to be an internment camp or large prison rather than a death camp. His superiors approved the plan and provided him with a false identity card in the name of "Tomasz Serafiński." On 19 September 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). After two days detention in the Light Horse Guards Barracks, where prisoners suffered beatings with rubber truncheons, Pilecki was sent to Auschwitz and was assigned inmate number 4859."
http://en.wikipedia.org/wiki/Witold_Pilecki
"In 1940, Pilecki presented to his superiors a plan to enter Germany's Auschwitz concentration camp at Oświęcim (the Polish name of the locality), gather intelligence on the camp from the inside, and organize inmate resistance. Until then, little had been known about the Germans' running of the camp and it was thought to be an internment camp or large prison rather than a death camp. His superiors approved the plan and provided him with a false identity card in the name of "Tomasz Serafiński." On 19 September 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). After two days detention in the Light Horse Guards Barracks, where prisoners suffered beatings with rubber truncheons, Pilecki was sent to Auschwitz and was assigned inmate number 4859."