Where does the U.S. government hold Unit 731 Shiro Ishi's research?

Given the fact that a deal was cut which agreed that the U.S. would not prosecute Unit 731 staff in exchange for the notes of experiments better clified as torture, I am sure the information is not readily available to the public. I would think it was originally in the custody of military intelligence and shared by them with a few other entities; however, given the length of time that has ped probably it is now stored in the National Archives or Library of Congress. I do not know when, if ever, it would become available. Probably at this point one could successfully sue for the release of the information, but the original method of obtaining these notes is so disgraceful and criminal the notes may never be released.