Jewish academic societies and the Serbian government representatives to the United States, Greif assisted the exhibition Jasenovac 75 in New Jersey covering crimes committed by Croatian Ustaše in the Jasenovac concentration camp, including genocide against the Serbs. In January 2018, with Serbian representatives Greif co-organised the exhibition Jasenovac - pravo na nezaborav at the United Nations in New York. The exhibition was criticized by the Croatian MVEP for "spreading false information and propaganda". Greif spent four years examining archives in research of the genocide in fascist Independent State of Croatia, in which he affirmed a number of more than 700,000-800,000 Serb victims in Jasenovac. Dr. Robert Rosett, Senior Historian at the International Institute for Holocaust Research at Yad Vashem, stated that the number of victims murdered at Jasenovac were "many times less than the grossly inflated count of more than 800,000 that was widely touted in the Communist era and has been endorsed by Gideon Greif". Journalist Alexander Brezar of Haaretz wrote that Greif is "popular among Serb nationalists and revisionists for repeatedly inflating the number of Serb victims at Jasenovac." According to the United States Holocaust Memorial Museum, somewhere between 77,000 and 99,000 Serbs, Jews, Roma, and Croat opponents of the Ustaša regime were killed at Jasenovac, of whom between 45,000 and 52,000 were ethnic Serbs. Srebrenica Commission In 2019, Grief was appointed by Bosnia's member of presidency and Serb entity Republika Srpska leader Milorad Dodik to head a independent International Commission of Inquiry to probe the events of the Srebrenica massacre during the war in Bosnia and Herzegovina (1992-1995). The concluding report published in July 2021 denied genocide in Srebrenica, "also repeatedly casts the Bosniaks as aggressors and the Bosnian Serbs as victims" prior to 1995. The International Criminal Tribunal for the former Yugoslavia as well as the International Court of Justice and domestic courts have characterised these killings as genocide. American and U.N. diplomats and the Srebrenica Genocide Memorial Center commented that the commission was a bid to rewrite history, as the Republika Srpska's officials, including Milorad Dodik, had openly minimised the number of killed or denied it was a genocide. General Counsel of the World Jewish Congress, Menachem Z. Rosensaft, who teaches genocide law at Columbia Law School, strongly criticised the report, calling it an "embarrassment". Brezar commented that Serb nationalist politicians "are hiring Jewish experts on the Holocaust – and not for their expertise. Rather,