The content of this answer is very graphic.
In 1990, the Australian Public Prosecutor's Special Investigations Unit (SIU) assembled a team of forensic archaeologists to unearth the site of a mass grave. The grave was located in Serniki, Ukraine, and the bodies were of local Jews who had been murdered in 1942. Three Ukrainian individuals, accused of having participated in this act of genocide, were undergoing trial in 1990 in Adelaide.
The chief archaeologist was Dr. Richard Wright. Along with a few other prosecutors and investigators, he later ended up serving at the International Criminal Tribunal for the Former Yugoslavia (ICTY), where they excavated several more mass graves, and collected forensic information that also pertained to the act of genocide.
For an overview of his findings, you can see: Richard Wright, "Where are the Bodies? In the Ground", The Public Historian 32:1, (February 2010), 96–107.
WARNING: THE FOLLOWING PHOTOS INCLUDE STRONG IMAGES
Wright describes the evidence found at Serniki, and how the way the bodies were placed there aligns with our understanding of how many of these mass murders took place. Victims were forced to descend into the hole and lie face down on top of a pile of corpses. And then they shot them in the back of their heads.
The man who developed this particular technique (called the "sardine method") was Obergruppenführer Friedrich Jeckeln. Eyewitnesses had already provided the details, but the discovery of the actual corpses served to confirm the information. While this was not the case at Serniki, some of the corpses in other mass murder holes that were excavated still had their house keys with them. These people expected to go home at the end of another normal day.
Obergruppenführer Friedrich Jeckeln
It is quite common to discover skeletons of small children (sometimes even newborns), as well as to discover corpses that still have all their hair. To my mind, this is all terribly scary, but what horrifies me the most is Wright's description (in the same article) of an excavation he conducted in Croatia in 2000.
In one specific location, the Croatian army is said to have been responsible for murdering Serbian citizens in 1993. Since these were crimes committed by the government at the time, the archaeologists needed to be supervised by the local police, special forces and Croatian secret service. They kept saying that the archaeologists were wasting their time, and that they would find nothing but the bodies of Serbian soldiers.
Wright describes how they found bodies of women and children, and how some of these skeletons were still dressed in evening gowns, and how some still had long, braided hair. Croatian intelligence representatives tried to inform archaeologists that "everybody knew" that this was how Serbian soldiers used to dress up, but I don't think anyone took their claims too seriously.
