Most of us have heard of the scientific experiments done on Jews and POWs by Germany during WWII. Less well known are similar experiments done by the Japanese. See the following 2 part video that takes a look at the atrocities that were committed and learn of the cover-up by the United States.
Here is an article that you may be interested in. This is the article that piqued my interest in Unit 731.
The National Archives also has information on this that offers an extensive look at Japanese war crimes.