 Complete the following phrase:  Schapers death squad was deployed in the newly formed Bezirk Bialystok district soon after the German invasion of the Soviet Union. Himmler visited Białystok on 30 June 1941 and pronounced that more forces were needed in the area, because the massive chase after the fleeing Red Army left behind a security vacuum. On 3 July an additional formation of Schutzpolizei arrived in the city from the General Government, led by SS-Hauptsturmführer Wolfgang Birkner, veteran of Einsatzgruppe IV from the Polish Campaign. The relief unit, called Kommando Bialystok, was sent in by SS-Obersturmbannführer Eberhard Schöngarth on orders from the Reich Security Main Office RSHA, due to reports of Soviet guerrilla activity in the area with Jews being of course immediately suspected of helping them. On 10 July 1941 Schapers Einsatzgruppe was subdivided into dozens of smaller commandos Einsatzkommandos numbering from several to several scores of people whose mission was to kill Jews, alleged communists and Soviet NKVD collaborators in captured territories often far behind the advancing German front. The entire Einsatzgruppe employed the same, systematic method of mass killing in many Polish villages and towns in the vicinity of Białystok. Schapers murderous rampage south-east of East Prussia included Wizna end of June, Wąsosz 5 July, Radziłów 7 July, 