In February, Japanese authorities began excavating the site of a former medical school that may reveal dark secrets about the country's WWII-era biological weapons program:
The investigation begins Monday at the former school linked to Unit 731, a germ and biological warfare outfit during the war. Shadowy experiments conducted by the unit on war prisoners have never been officially acknowledged by the government but have been documented by historians and participants.
It is the first government probe of the Tokyo site, and follows a former nurse's revelation that she helped bury body parts there as American forces began occupying the capital at the end of the war...
The former nurse, Toyo Ishii, now 88, broke 60 years of silence in 2006, saying she and colleagues at an army hospital at the site were ordered to bury numerous corpses, bones and body parts during the weeks following Japan's Aug. 15, 1945, surrender before American troops arrived in the capital.
The subjects of experimentation were thousands of prisoners captured during Japan's invasion of China and Korea. The United States granted immunity to Japanese leaders for providing access to the research:
According to historical accounts, male and female prisoners, named "logs" by their torturers, were subjected to vivisection without anaesthesia after they had been deliberately infected with diseases such as typhus and cholera. Some had limbs amputated or organs removed.
Leading members of the unit were secretly granted immunity from prosecution in return for giving US occupation forces access to years of biological warfare research. Some went on to occupy prestigious positions in the pharmaceutical industry, health ministry and academia.
Japan's push into China began in 1931, and had become an occupation of large areas of the country by 1937, the year of the notorious Nanking massacre, in which, by some historical estimates, between 250,000 and 300,000 people in the city were killed.
Rape of Nanking
To avoid being charged for their crimes, Japanese officials are believed to have bribed Americans using riches stolen from Nanking and other sites during the war.