Mass murder of Jews is documented.Look here from the Stroop report of the 1943 destruction of Warsaw ghetto. https://phdn.org/archives/holocaust-history.org/works/stroop-report/htm/strp034.htm Another report From C. Sturdy Colls, M. Branthwaite, "'This is Proof'? Forensic Evidence and Ambiguous Material Culture at Treblinka Extermination Camp", International Journal of Historical Archaeology, 2017, 22(3), pp. 430–453: The excavation of Trench 4 confirmed that the 22 × 15 m anomaly in the GPR results did in fact represent the foundations of the first gas chambers built by the Nazis at Treblinka (known as the old gas chambers), which existed at a depth of 0.85 m below the ground. Seven hundred twelve individual items were also recovered from this small trench. These items can be divided into three groups: (1) Building materials – e.g., tiles, bricks, and plaster (2) Personal belongings – e.g., jewelry, hair clips, a belt buckle, and coins (3) Functional items - scissors, a knife, bullets, a battery, glass, etc. A selection of the items found are shown in Fig. 2 Dentures, and gold and silver teeth were also found along with a considerable amount of fragmented human remains, some of which exhibited evidence of burninga some that did not. All of these different types of material traces were commingled, confirming the nature of destruction afforded to the gas chambers in autumn 1943 and the heavily disturbed nature of the ground exhibited in the GPR results. This wasf established by the discovery of 286 objects in Trench 3, which existed outside of the area of the gas chamber foundations. The items found in this area can also be grouped into the categories outlined above and human remains were also found intermingled with the objects in this area. https://1.bp.blogspot.com/-dmSRCrNvRas/Xb1Els-1PiI/AAAAAAAAAk4/HG4vNEGGwkANzNwcmZ3LWSVy9hEyNFQyQCLcBGAsYHQ/s1600/2703715_preview_wm%255B1%255D.jpg