During the Soviet struggle to establish control over Western Ukraine, NKVD units dressed as UPA fighters[1] committed atrocities in order to demoralize the civilian population, and to turn the people against nationalist groups.
[3] Since summer 1945 the fact of such group existence also became known for OUN/UPA, thus the NKVD stopped new groups creation and rejoin the existing to larger size formation (initially they can have from 3 to 50 persons depending on task).
4/001345 from Military Judge of Ukrainian area to Khrushchev, some special groups committed atrocities against the civil population in order to falsify their links with OUN/UPA and summon faked OUN/UPA detachments, sometimes even they exterminate Soviet agents from other region or authority .
In many cases such “crimes against Soviet law” were hidden by local regional MGB staff, nevertheless some of such “groups” were prosecuted by Military Court.
[4] In 2008, the Security Service of Ukraine (SBU) has published information about the actions of special groups from the NKVD posing as fighters of the Ukrainian Insurgent Army (UPA) and the Organization of Ukrainian Nationalists (OUN) in the western regions of the Ukrainian Soviet Socialist Republic during the 1944-1954 period.