Szare Szeregi
Jan Więckowski joined PET in 1940. PET was a small organization created by Polish students which allowed young Poles to continue their education in the Polish Underground. Through PET, Jan completed his schooling and passed his Matura examination in 1941. Once PET merged with the Gray Ranks, Więckowski was assigned to the southern scouting team "SAD-400", commanded by his former classmate Andrzej Romocki. The unit specialized in minor sabotage and was referred to by the codename "Wawer". Więckowski took part in "Operacja Lornetka" (Operation Binoculars) - an intelligence-gathering operation that allowed for the planning of another operation which concluded with the bombing of a German Wehrmacht troop transport train near Gołąb on June 30, 1943. In late August 1943, Battalion Zośka was established, and Więckowski was appointed Chief of the 2nd Company, nicknamed "Company "Rudy"". On June 1, 1944, he was appointed Chief of Security for all of Battalion Zośka. He was responsible for the preparation of all platoons in the battalion during sabotage and diversion operations, which included the notable Operation Kutschera - the successful assassination of SS and Reich Police Chief of Warsaw Franz Kutschera. In 1944, Więckowski graduated from the second round of training at the underground Infantry Cadets Reserve School "Agricola". Wieckowski's mother - Helena Więckowska, was a member of the secret Government Delegation for Poland subordinated to the Polish Government in Exile and helped teach in the underground's school system.