In mid-August 1943 a Polish unit of the Uderzeniowe Bataliony Kadrowe (English: Striking Cadre Battalions, UBK), which was controlled by the right-wing organization Konfederacja Narodu, organized armed attack on East Prussian villages in the area of Johannisburg (now: Pisz). The attack was made as revenge for German genocide and atrocities committed against Polish population. The targets of the attack included devoted Nazis, members of NSDAP and inhabitants engaging in brutality against Polish population. According to Polish sources, some 70 Germans were killed and 40 German farms were razed to the ground, while an eyewitness reports 13 killed people, including a woman and two children, and two people wounded. The attack, commanded by Colonel Stanislaw Karolkiewicz, was a revenge for Germa