The article discusses hitherto little-known events of a Polish–Ukrainian conflict in the north-western part of the Przemysl district (between Dynow and Przemysl) during the first months of 1945. The conflict was embittered by murders which had been committed on individual Poles in the beginning of 1945. In turn, over thirty assaults on Ukrainian people took place from February till June that year. Attacks on: Skopow village on the 27th of March (61 were killed), Brzuska on 11th of April (187 victims), Bachow (95 victims) and Malkowice (at least 116 were killed) rank among the biggest ones. At the time of other attacks amid those killed were Greek Catholic priests and the members of their households. Partly, those murders were committed to pressurize local Ukrainians into emigrating to the Soviet Ukraine within the framework of the contemporary population displacement. Both the police and the Security Service failed to ascertain and capture the perpetrators. The assaults on the Ukrainian population stopped in June 1945, probably as a result of an agreement between the underground independence movement and representatives of the local OUN–UPA structures. It is impossible to establish who committed the murders of the local Ukrainians. After having analyzed the available documents (Polish and Ukrainian), reports of the suspects who were questioned by SB officers and witness accounts and also the course of events, the author came to a conclusion that at least some of those attacks were carried out by groups of the Polish underground movement under command of Roman “Sęp” Kisiel, who during the occupation was a commandant of BCh in the Przemysl district. In autumn 1944 on the basis of his former subordinates from local posts of BCh, part of whom worked in the police, he created the People Security Service in order to protect the Polish locals. It is hard to asses the exact numbers of this organization but in July 1945 1746 people revealed themselves as its members to the chief of the WUBP in Rzeszow. The SB officers ascribed to Kisiel’s groups twelve raids that caused the deaths of over 500 people. Nevertheless he was not brought to account for that. The responsibility for some of those attacks is probably held by minor Polish robber bands or neighbouring units of the underground movement.