A main area of the group's focus was also on "blackout burglary," considered a serious problem during bombing raids when criminals would raid abandoned homes, shops and factories for valuables. The Kripo was one of the sources of manpower used to fill the ranks of the Einsatzgruppen and several senior Kripo commanders, Arthur Nebe among them, were assigned as Einsatzgruppen commanders. The Einsatzgruppen's mobile killing units were active in the implementation of the Final Solution, in the territories overrun by the Nazi war machine; which culminated in the Holocaust.[9]