On July 26, 1941 the Germans ordered all the Jews of Biržai to leave their homes and move to a ghetto that was set up on a few streets around the synagogue and beit midrash.
Jewish men were taken from their homes to the Jewish cemetery and to other places in town and shot. According to the Soviet Extraordinary Committee for the Examination of Nazi Atrocities, 30 bodies of Jewish victims were found in the cemetery, most of these victims had been shot in the head.

More information: Yad Vashem

On August 8, 1941 groups of Jewish women, men, and children from the Biržai ghetto, 100-200 of each, were taken to the Astrava Forest, located 3.5 kilometers south of the town, and 1.5 kilometers from the road leading to Paroveja. Five hundred Jewish men had to dig two pits, 20-30 meters long and 2 meters wide. During the digging the Lithuanian guards abused the men. Before being taken to the pits, the victims had to take off their clothes and, in groups of 10, they were pushed into the pits and shot to death. After carrying out the massacre, which lasted eight hours, the perpetrators returned to town singing. The looted Jewish possessions were divided among the German and Lithuanian murderers. According to Soviet sources the bodies of 2,400 Jews, including 900 children, were found in the two pits.

More information: Yad Vashem