The first such transport of a small number of prisoners (the first out of six) was reported on March 19, 1942 by Rabbi Aaronson who related that the Gestapo (he probably confounded it with the SS) created a list prior to the selection and informed the selected prisoners that they would be transferred to a hospital and eventually to a place with better and easier work conditions.
The SS did not name any destination. However, Rabbi Aaronson presumed that their destination would be Chełmno, based on his in-depth knowledge of the area (he had spent several years in Konin and its surroundings), and on the report of an escapee from Chełmno. In January 1942, i.e. prior to Aaronson's deportation to Czarków, Abraham Cohen (or Kohn), another resident of Sanniki, informed Rabbi Aaronson that many local Jews were gassed in Chełmno and explained the way the death camp worked.
Aaronson's details, consistent with the proven knowledge about Chełmno, which he called in his diary "the valley of the shadow of death," written in the spring of 1942, could not have come from anybody else other than an eyewitness. The source of information was indeed an escapee named Michał Podchlebnik who met Cohen in Gostynin shortly after he escaped. Podchlebnik, a Jew from the village of Bugaj (Bugitten) in Landkreis Wartbrücken (about 18 km from Koło-Warthbrücken), who was deported to Chełmno (probably on January 10, 1942), was selected to the Waldkommando (forest command), a gravediggers squad, excavating the pits in which the victims of the gas vans were buried. He was one of three known prisoners who escaped from the mass burial zone into the surrounding forest, and was a key witnesses in 1945 at the Chełmno trials of the former SS men from the SS Special Detachment Kulmhof....