A Nazi diary written by the party's chief ideologue was discovered after missing for 70 years. The diary, written by Nazi Party leader Alfred Rosenberg's diary, offers valuable insights into the Third Reich. The Nazi diary was used against Rosenberg in at the Nuremberg trials. Rosenberg was hanged in 1946. The Nazi diary was a loose-leaf collection of notes Rosenberg kept from the years 1934 to 1944.

The decades-long search for the missing Nazi diary that was likely smuggled out of Germany by one of the Nuremberg prosecutors is "one of great detective stories of our time," according to the director of U.S. Immigration and Customs Enforcement Agency.

Alfred Rosenberg was the Nazi party's chief ideologue. He became a confidante of Adolf Hitler after they met in 1921. Rosenberg joined the party before Hitler. He gained fame by editing the Nazi newspaper and writing anti-Semitic propaganda tracts for the party. Rosenberg moved up in the Nazi Party until he was named the foreign policy office head. Rosenberg was one of the chief architects of the plan to systematically exterminate Jews.

Rosenberg was convicted of war crimes at the Nuremberg International Military Tribunal. He was hanged in October 1946. Parts of his diary were used by the tribunal.
The missing 400 pages of the diary was tracked down by the U.S. Immigration and Customs Enforcement Agency which was working with the U.S. Holocaust Memorial Museum and investigators in Delaware. Scholars believe it will shed light on how the Nazis operated in the years before and during World War II.

ICE Director John Morton told CNN "This is one of the great detective stories of our time. The diary was known at the time of the military tribunal in Nuremberg when the leadership of the Nazi Party was tried and it then disappeared for nearly 70 years. It was in fact smuggled out of Nuremberg into the United States, probably by Robert Kempner, who was one of the prosecutors for the United States in Nuremberg."

In November 2012, Department of Homeland Security and Delaware United States Attorney's office investigators got a tip in November 2012 from an unnamed "source," an art security specialist working with the Holocaust Museum. Investigators are now trying to determine how the papers ended up in the possession of Herbert Richardson, an academic in Buffalo, N.Y.

The Nazi diary will eventually be given to the Holocaust Museum, where it will be accessible to scholars and the public.