In 1939 the village of Zalesie Koropieckie had 150 homesteads and 696 inhabitants. Ukrainians predominated, there were more than 200 Poles and about 10 Jews.

On 7 or 8 February 1945, Ukrainian Insurgent Army's (UPA) militia returning home from the massacre of the Polish population in Barysh entered the village and started murdering Poles and plundering their property. According to witnesses, 40-50 people were murdered. Some of the victims were residents of the nearby village of Puźniki and were buried there. The remaining remains of the victims were collected and buried in the cemetery in Zalesie Koropieckie in a mass grave near the Orthodox church.

After the war, the local authorities erected a monument to the murdered. The grave is situated near the entrance to the cemetery, to the right of the Orthodox church; it is clearly visible from the road leading through the village. It is an earthen grave, walled with concrete. The grave was planted with flowers and decorative vegetation. The inscriptions are only in Ukrainian; no nationality is given next to the names of the victims. The memorial consists of two rectangular concrete blocks, stacked one on top of the other. On the upper block is a plaque with a bas-relief of a mother cuddling a child, on the lower block is engraved an inscription and 34 names of the victims. To the right of this obelisk is a cross on a stone pedestal, on which is affixed a plaque with a faint Ukrainian inscription. The inscription on the obelisk reads: "Victims of the tragedy on 6 February 1945 in the village of Zalesie / [further incomplete list of names - only 34 people]". The inscription on the pedestal of the cross reads: "Here rest 38 victims of 1945".