EN
World War II was the time of anomie, the time when the worst human features were revealed. Cases in which neighbours turned into victims and executioners were not rare. Such cases also occurred in the territory of north-eastern Mazovia, among others in Wąsosz. According to various estimates from 150 to 250 Jews were killed there by their 20 to 30 neighbours. The article presents a new source of research of this incident. In 2003, during archeological excavations, depository of books, containing prayer-books and other religious books, Talmudic and literary works, was found in Piaskowa Street. The depository must have been hidden there right before the pogrom by one of the victims.