On September 5, 1941, a unit of the SiPo (the German security police) from Wolożyn came to Iwieniec and ordered the local police to assemble the Jewish men in the market square. The Germans accused the town's Jews of noncompliance with their orders, and demanded that the Jewish community pay a ransom to free the hostages. After receiving the ransom payment, the Germans did not release the hostages; instead, after subjecting them to beatings and abuse, they took the 50 (or 76, according to another source) men northward and shot them dead. Eyewitnesses later claimed that the killing site lay in the vicinity of the village of Korduny, about five kilometers northeast of Iwieniec. The exact location of this site is unclear.

More information: Yad Vashem

On Saturday, June 28, 1941, the second day of the German occupation of Iwieniec, the occupiers killed 34 Jews. Earlier, during the fighting over the Iwieniec area, the Soviets had downed a German plane. Its wounded pilot was taken to a Soviet hospital in the town, where he died. The occupiers accused the Jews of "deliberate medical malpractice". They assembled the male Jews in the market square, arranged them in rows, picked 35 men, escorted them to a nearby forest, and shot them. One of the men, who was only wounded in the shooting, was later rescued by Jewish laborers who had been brought to this place to bury the dead. Eyewitnesses failed to identify the forest where the massacre had taken place. However, since the sounds of gunfire could be heard in the town itself, it must have been the Piszczugi Forest, which lies less than one kilometer north of Iwieniec. On June 8, the Nazis took 40 ghetto inmates to the square near the "red brick" Catholic church, led them into the Pishchugi Forest, and ordered them to dig a deep, long pit. The next morning, on June 9, 1942, a squad consisting of 12 Germans and 17 Lithuanian auxiliaries came over from Baranowicze. With the assistance of the local police, they took all the inmates of the Iwieniec Ghetto (who numbered either around 800 or 1,025, depending on the source), except for several "specialists", to the pit in the forest and shot them with machine guns. Many of the victims were buried alive, having been merely wounded in the shooting.

More information: Yad Vashem

A group of Iwieniec Jews appears to have been shot in mid-July 1941, two weeks after the first massacre of June 28, 1941. According to several sources, some local residents compiled a list of Jews and presented it to the Germans, claiming that these Jews were Communists. Thirteen Jews from this list, mostly men, were arrested and locked in the cellar of a pharmacy, while the rest managed to hide. The victims were later taken out of the cellar to the area near the cemetery, known as the New Town, where they were tortured and then shot dead. The sources indicate that one of the victims was a former Polish sergeant who had converted to Judaism.

More information: Yad Vashem