Ohio State international law professor John Quigley will be heading to the Columbus Museum of Art tonight to share his experience as an expert witness in the controversial trial of Khmer Rouge officials. His lecture coincides with the museum’s photography exhibit, “Facing Death: Portraits from Cambodia’s Killing Fields,” and his upcoming book, “Genocide in Cambodia: Documents from the Trial of Pol Pot and Ieng Sery.”Quigley’s book documents the entire trial of the two leaders of the Khmer Rouge, the Maoist faction that ruled Cambodia from 1975 to 1979.During that time in Cambodia, nearly 20,000 people were brought to S-21, an execution site for those who committed treason and other crimes against the Khmer Rouge. Many family members of these alleged traitors were also killed at S-21 to prevent an uprising. The prisoners were often tortured and photographed prior to their execution. The photos were sent to Khmer Rouge authorities as evidence of the victims’ deaths. In 1993, two Americans, Douglas Niven and Christopher Riley, found negatives of the photographs and compiled them to form the Cambodia Genocide Photo Archive Group. Those photos represent the human suffering that took place during that time.In 1979, Quigley was sent to Cambodia to help determine the international meaning of “genocide” in order to convict those involved with the S-21 executions. Since then, he has been working on his book, which draws on his participation in the trial and his time in Cambodia.”This was one of the more horrifying instances in recent history. I think it is appropriate that there should be acknowledgment of it,” Quigley said. “It is a timely event, considering this week marks the 25th anniversary of the coming of power of the Khmer Rouge.”The photography exhibit displays 100 pictures of the executed prisoners. “This is just a fraction of an archive of a fraction of the number of people killed. I think it is important to realize that,” said Catherine Evans, photography curator at the Columbus Museum of Art.Evans said the display is meant to raise consciousness about this period and to help avoid future instances of genocide.”When I heard about (Quigley’s) work, I thought it was a great marriage between the photo exhibition and his book,” Evans said. The event is a collaboration between the museum and the Columbus Council on World Affairs, said Paul Mollard, educator of adult programs at the museum. The exhibition was organized by Boston University and will continue to travel over the next year. Quigley’s book is set to be released by the end of the month. His lecture begins at 6 p.m. and admission is free. The exhibit will last through May 28.