I recently read about Shirō Ishii, a Japaneese microbiologist (https://en.wikipedia.org/wiki/Shirō_Ishii) who conducted human experiments during World War-II which resulted in death of close to 10000 humans. More interestingly he was given immunity from war crimes in exchange for full disclosure about his experiments. And the information he provided was deemed invaluable. From the wiki

  it (experiment information) "could never have been 
  obtained in the United States because of scruples 
  attached to experiments on humans," and "the information 
  was obtained fairly cheaply."