 As a result of the secretive Sonderaktion 1005, the camps were dismantled by commandos of condemned prisoners, their records were destroyed, and the mass graves were dug up.Some extermination camps that remained uncleared of evidence were liberated by Soviet troops, who followed different standards of documentation and openness than the Western allies did.Nonetheless Majdanek was captured nearly intact due to the rapid advance of the Soviet Red Army during Operation Bagration.