February 9, 1943, is considered the beginning of the genocide committed by Ukrainian nationalists on Poles. It was on that day when the Polish village of Parośla, also known as Kolonia Parośla I, ceased to exist.
As a result of the German and Soviet invasion of Poland in 1939, Poland was divided between those aggressors. In 1941, after the Third Reich attacked the Soviet Union, all areas belonging to Poland before 1939 were under German occupation. Ukrainian nationalists relied on the help of the Germans in the establishment of their state and many of them worked in the Ukrainian Auxiliary Police (Ukrainische Hilfspolizei). Members of that formation took part in German crimes against the Jewish population murdering approximately 450,000 Jews in south-eastern Poland occupied by the Third Reich in 1941-1943.
At the end of 1942, a branch of the Organization of Ukrainian Nationalists led by Stefan Bandera (OUN-B) established the Ukrainian Insurgent Army (UPA). The ranks of this organization were often supplied with deserters from the Ukrainian police.
On the night of February 8-9, 1943, a UPA squad commanded by Hryhorij Perehijniak entered the village of Kolonia Parośla I in Volhynia, claiming to be a group of Soviet partisans. The villagers were forbidden to leave their premises and ordered to accommodate the members of the squad. In the afternoon, Poles were informed that they would be bound before leaving. This was supposed to protect them from the German revenge for helping the partisans but it triggered the slaughter of the defenceless and innocent population. The vast majority of inhabitants were murdered with axes and knives. No one was spared, neither women nor children who were several months old. According to various sources, between 149 and 173 people were murdered within a few hours. Only about 10 inhabitants of Parośla survived the massacre including the six-person Jewish family of Dawid Balzer, who were hidden in the buildings belonging to Klemens Horoszkiewicz. The owner of this house and his relatives were also brutally murdered.