The operations were mostly carried out on 31 August 1939.[7] The operation - as well as the main German offensive - was originally scheduled for 26 August; the shifting diplomatic situation resulted in delay until 31 August/1 September - but one of the German undercover units was not informed and carried out its attack on a German customs post; several Germans were killed before the incident ended.[8] The operations were carried by agents of the SS[7] and the SD.[3] The German troops, dressed in Polish uniforms, would storm various border buildings, scare the locals with inaccurate shots, carry out acts of vandalism, and retreat, leaving behind dead bodies in Polish uniforms.[9] The bodies were in fact prisoners from concentration camps; they were dressed in Polish uniforms, killed (by a lethal injection, then shot for appearance) and left behind.