Mass graves uncovered in Syria in the days since President Bashar al-Assad was overthrown are exposing evidence of some of the worst abuses since the Nazis, a top international war crimes prosecutor said. More than 100,000 people were tortured and killed in the state-run "machinery of death," Stephen Rapp, former U.S. war crimes ambassador at large, told Reuters on Tuesday after visiting two mass grave sites in the towns of Qutayfah and Najha near Damascus. "We really haven't seen anything quite like this since the Nazis," Rapp said of the evidence emerging from the mass graves. "From the secret police who disappeared people from their streets and homes, to the jailers and interrogators who starved and tortured them to death, to the truck drivers and bulldozer drivers who hid their bodies, thousands of people were working in this system of killing," he said.