Exchange of Data for Immunity
In 1946, Colonel Murray Sanders, a microbiologist and member of America's military center for biological weapons, arrived in Yokohama, Japan to investigate Japanese biological warfare activity. He received information about the biological warfare research after threatening Unit 731 officers. Sanders took this information to General Douglas MacArthur. MacArthur made a deal with the Japanese informants, in which the physicians would obtain immunity if they gave only America their data. MacArthur had said, "Since it is believed that the USSR possesses only a small portion of the technical information, and since any war-crimes action would completely reveal such data to all nations, it is felt that such publicity must be avoided in the interests of defense and security of the U.S."
" Additional data, possibly some statements from Ishii probably can be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as 'War Crimes' evidence."- General Douglas MacArthur
"Before the tribunal, there was discussion among some member countries about putting Unit 731’s leaders on the stand, but eventually the occupation authorities – led by Gen MacArthur – decided not to try them. The Americans wanted to obtain information about germ warfare from the unit because it was already the early stages of the Cold War. .[The U.S. government] 'wanted to monopolize that information and struck a deal whereby the members of Unit 731 received immunity in exchange for their knowledge"- Masataka Mori, a professor of history at Shizuoka University in Japan
General Douglas MacArthur
(Courtesy of biography.com)