The Bielski's parents and older family members were killed in the ghetto on 8 December 1941. The four Bielski brothers - Tuvia, Alexander (also known as "Zus"), Asael, and Aron Bielski - managed to escape to the nearby forest. Together with 13 neighbours from the ghetto, they formed their partisan combat group in the spring of 1942. Originally, about forty people were in the group, but it grew quickly.