WASHINGTON - The long-lost diary kept by a top aide to Adolf Hitler as he oversaw the genocide against Jews and others during World War Two, a key piece of evidence during the Nuremberg trials, was handed over on Tuesday to the US Holocaust Museum.US Immigration and Customs Enforcement agents found and seized Alfred Rosenberg's 400-page diary in Wilmington, Delaware this year, ending a nearly 70-year hunt for the diary which disappeared after the Nuremberg trials in 1946."The finding and return of the Rosenberg Diary is one more small but significant step towards a full and complete understanding of the depraved mindset of those responsible for the mass killing of Jewish people and ethnic groups during World War Two," said US Attorney Charles Oberly. Rosenberg was privy to much of the planning for the Nazi state, the mass murder of the Jewish people and other ethnic groups as well as planning of conduct of World War Two.Rosenberg was a defendant at the Nurembreg Trials in Germany, from 1945 to 1946. He was found guilty on all four counts of the indictment for conspiracy to commit aggressive warfare, crimes against peace, war crimes and crimes against humanity. Rosenberg was hanged on October 16, 1946.After the surrender of Germany in 1945, Allied forces took ownership of all documents created by the defeated German government. To prepare for war crimes trials, US government agencies selected relevant documents as potential evidence, including the Rosenberg diary.One of the prosecutors at the Nuremberg Trials, Robert Kempner, removed various documents including the Rosenberg diary from US government facilities in Nuremberg and smuggled them back to the United States.After Kempner's death in 1993, heirs to his estate agreed to forfeit his possessions to the US Holocaust Museum, but the diary was not among them. The museum began searching for it and eventually Immigration and Customs Enforcement agents found and seized the diary.ICE's Homeland Security Investigations special agents focus heavily on criminal investigations that involve the illegal importation and distribution of cultural property.