Between June 29 and July 15, 1942, the Germans liquidated the Słonim Ghetto. The Nazi authorities decided to delegate this task to SS units from faraway Minsk and Baranowicze, preferring not to rely on the local SS and policemen, who were allegedly too familiar with the Jews of Słonim. Nevertheless, the 727th Infantry Regiment of the Wehrmacht also took part in the roundup of the Jews, just as it had done during the second massacre in November 1941. The final liquidation was assigned to Stabsleiter Rithmeyer. This third and largest, massacre of Jews was preceded by a wave of arrests and executions of anti-Nazi Poles. The Nazis shot several dozen Polish arrestees at the Pietralowicze Hills, the site of the first mass murder of Jews in July 1941. When forty trucks bearing SS squads and Latvian collaborators arrived in the town in late June 1942, many ghetto Jews ascribed their arrival to the ongoing anti-Polish campaign, and thus did not panic.
However, at dawn on June 29, 1942, the SS and Security Police squad that had arrived from Minsk began to encircle the Słonim Ghetto. When Rithmeyer shot Kwint, the deputy chairman of the Jewish Council, at point-blank range, the ghetto Jews finally realized what was going on and began to hide. There were attempts at resistance on the part of a clandestine cell that had managed to procure some arms. The SS set the ghetto (and the whole town of Słonim) on fire. The “operation” dragged on for longer than the Germans had anticipated. Rithmeyer was forced to spare the Jewish craftsmen and medical personnel (700 men and 100 women). Nevertheless, over the next two weeks his squad murdered 8,000-10,000 (the figure varies depending on the source) inmates of the Słonim Ghetto. The victims were either killed on the spot or escorted to Pietralowicze Hill and shot there.