Department of Justice Official Releases Letter Admitting U.S. Amnesty of Japan’s Unit 731 War Criminals

Jeffrey Kaye
30 min readMay 14, 2017

Upon my request, both the Department of Justice (DOJ) and the Simon Wiesenthal Center have released copies of a December 1998 letter from DOJ official Eli Rosenbaum to Rabbi Abraham Cooper of the Simon Wiesenthal Center. In the letter, Rosenbaum admitted to Cooper that after World War II the United States government had classified records pertaining to a Japanese military unit that engaged in biological warfare experimentation and field trials on humans.

The letter, one of two released to this author, confirmed the U.S. “essentially assisted Japan in covering up the atrocities perpetrated by the unit.”

In 1998, Rosenbaum was director of DOJ’s Office of Special Investigations (OSI), while Rabbi Cooper was associate dean of the Wiesenthal Center. The occasion for the correspondence was the Wiesenthal Center’s sponsorship of a “Trans-Pacific Video-Conference on Japanese Wartime Atrocities,” held at the Center’s own Museum of Tolerance on August 16, 1998.[1]

Reported briefly in the press at the time,[2] Rosenbaum’s letter of December 17, 1998 ended any doubts that the U.S. government had given scientists and military personnel associated with the notorious Japanese biological warfare program of the 1930s-1940s “immunity [from prosecution at the International Military Tribunal, Far East] in return for their human experimentation research data.”[3]

This appears to have been the first time that any U.S. government official admitted publicly and officially that the U.S. had proposed an amnesty for the members of Japan’s Unit 731 and assorted components, known to have murdered thousands of prisoners in illegal biological experiments, and hundreds of thousands of soldiers and civilians in biological warfare operations predominantly in China, but also the Soviet Union, from 1939 until nearly the end of World War II.

While Rosenbaum’s letter was quoted in the press, and in a 2002 Congressional Research Service report, the letter itself, and a November 1998 letter to Cooper also on the subject of Japan’s war crimes, were never released publicly. These letters are now…