TOKYO, May 31 (Xinhua) -- Historical documents presented to the Japanese Defense Agency on Wednesday reveal that the Japanese Army destroyed evidence of biological weapons development in China upon surrender in 1945, Kyodo News reported.

    The Niiduma documents, named after Seiichi Niiduma, a deceased former army officer in the Imperial Japanese Army, also show that at the end of World War II, the United States occupation authority had exempted Japan from liability of having conducted human experiments in China.

    The documents included Niiduma's record of the Japanese Army ordering Unit 731 on Aug. 15, 1945 to have evidence of developing germ weaponry destroyed, as well as his records of the U.S. authority questioning himself and other Japanese officers, the report said.

    According to his records, the U.S. authority told Niiduma and others "not to mix scientific research with war crimes," which practically exempted Japan from liability of conducting human experiments in China.

    The bunch of documents, collected by Niiduma during the war, were given to a research institute of the Defense Agency on Wednesday by his second daughter Tomoe Obata.

    The documents also included a letter from Tomosada Masuda, an army doctor of Unit 731, to Niiduma in November 1945, which recorded that another army doctor, Ryoichi Naito, had proposed concealing the fact that human experiments were conducted in China. Enditem