Some of his better known skeletal confirmations are: John F. Kennedy, the men who fought in General Custer's "last stand", Dr. Josef Mengele, the famous Nazi war criminal who fled to Brazil the many victims of serial killer, John Wayne Gacey, Egyptian boy King Tutankhamun and the victims of the Oklahoma bombing. In the 1980's he went to Argentina to exhume mass graves filled with innocent civilians who had been killed by government death squads during the war. He has worked in Argentina, Guatemala, Ethiopia, Philippines, Croatia and others. So far his work has led to the conviction of five officers in Argentina.