Towards the end of October, the entire slave-labour workforce of KL Lublin/Majdanek including Jewish prisoners of the Trawniki concentration camp were ordered to begin the construction of trenches that would become mass graves. Although the trenches were supposedly for defense against air raids, and their zigzag shape granted some plausibility to this lie, the prisoners guessed their true purpose.:232:403–404:285–286 The massacres, later assumed to have been revenge for German defeat at Stalingrad, were set by Christian Wirth for November 3, 1943 under the codename Operation Harvest Festival, simultaneously at Majdanek, Trawniki, Poniatowa, Budzyn, Kraśnik, Puławy and Lipowa subcamps. The bodies of Jews shot in the pits by Trawniki men aided by Battalion 101 were later incinerated by a "Sonderkommando" from Milejów, who were executed on site upon the completion of their task by the end of 1943.