The village of Kupowalce was inhabited by 80% Poles, many of whom were of noble lineage.

In 1943, prompted by news of assaults on Poles, young people started to do night watch. On 16.07.1943, at noon, when everyone was busy with work and did not anticipate an attack, the UPA attacked Kupowalce and the neighbouring colonies (Szeroka and Lulówka). Attempts to defend themselves failed, as the Poles were scattered and did not even manage to draw their concealed weapons. In the general panic and confusion, the inhabitants saved themselves by fleeing. According to witnesses, about 150 people were killed. The property of the Poles was looted, then the village was burnt down. The victims were buried at the crime scenes, mostly in mass graves. The burial had to be taken care of by local Ukrainians on the orders of the Ukrainian Insurgent Army.

In 1998, the Association for the Commemoration of Poles Murdered in Volhynia erected a tall metal cross with a plaque in Kupowalce. The inscription reads: "To the 130 Poles / residents of the village of Kupowalce / who perished in 1943 / In eternal memory / Compatriots".

In 2008 and 2011, members of the Association carried out repair and renovation work on this commemoration.