The Group Thirteen network (Yiddish: דאָס דרײַצענטל) was a Jewish collaborationist organisation in the Warsaw Ghetto It took its informal name from the address of its main office at 13 Leszno Street in Warsaw. The group was founded in December 1940 and led by Abraham Gancwajch, the former head of Hashomer Hatzair in Łódź Sanctioned by Sicherheitsdienst (SD), and also known as the Jewish Gestapo,] the unit reported directly to the German Gestapo office
The group vied for control of the ghetto with the Judenrat, and infiltrated the Jewish opposition within the ghetto. The group’s most important branch was the Office to Combat Usury and Profiteering in the Jewish Quarter of Warsaw. Supposed to fight the black market, it actually collected large sums via racketeering, blackmail and extortions. The group also ran its own prison. In total, the group numbered between three and four hundred uniformed Jewish officers.