The National Archives of Japan has disclosed the names of 3,607 members of the Imperial Japanese Army’s notorious Unit 731, which conducted germ warfare and other biological experiments mainly on prisoners in China before and during World War II, according to a researcher.

Katsuo Nishiyama, professor emeritus of Shiga University of Medical Science and head of the group that requested the disclosure, told The Japan Times on Monday that “it is the first time that almost all of the real names and addresses of the unit’s members have been unveiled as a definitive and official document.”

The history of secretive Unit 731 had long been concealed. Its commander, Lt. Gen. Shiro Ishii, and others received immunity from prosecution by the International Military Tribunal for the Far East after giving the United States its data on germ warfare.

The list, dated Jan. 1, 1945, includes names, ranks and personal information — such as addresses and family members — of 52 surgeons, 49 engineers, 38 nurses and 1,117 combat medics, mainly those attached to the headquarters of the unit, which was officially known as the Epidemic Prevention and Water Purification Department of the Kwantung Army.

Nishiyama announced the disclosure of the list at a news conference Saturday in Kyoto.

The unit, which was established in 1936 to develop biological weapons, conducted research mostly using Chinese and Koreans who had been arrested on espionage charges. The research included infecting prisoners with germs before performing live vivisections on them, and deliberately causing frostbite to observe the process of necrosis.

A request to the national archives to disclose the list was first filed by a group led by Nishiyama in 2015. Initially, the released list was mostly blacked out. But almost all of the names and ranks of the members were declassified in January after negotiations. Personal information on some individuals remains secret.

A group led by Nishiyama plans to urge Kyoto University to determine the legitimacy of a university degree conferred on one of the medical officers in the unit, arguing his dissertation may have been based on experiments performed on living people.

The group has been collecting signatures to back its request.

Unit 731 was involved in research on more than 20 types of bacteria including anthrax, smallpox and botulinum. About 3,000 people worked at its headquarters in the suburbs of Harbin in what was then Manchuria. Historians believe that more than 3,000 people died in the human experiments.

A U.S. Army report dated May 5, 1982, stated that the desire of various U.S. committees to keep the information on the experiments out of the public domain as well as the hands of the former Soviet Union, also factored into the decision not to prosecute Ishii.

Although much of the information regarding the unit has been kept under wraps in the 70-plus years since the end of the war, Nishiyama said he hoped “the disclosure of the official documents will help in shedding more light on the unit and its history.”

When asked about the social impact he hoped the disclosure would have, he replied that he “personally believes that Unit 731 has a collective responsibility to account for its war crimes, and that those crimes must be atoned for as a way of showing that those crimes will never be repeated.”

The citizens’ group he leads is making a petition to have Kyoto University determine the legitimacy of a university degree conferred on a medical officer in the unit.

To support its case, the group’s website draws on examples of suspected human experimentation that were disguised as experiments on monkeys. One example refers to a “monkey” that “complained of headache, fever, and lost appetite” — circumstantial evidence that indicates the experiments were conducted on humans instead.

“Kyoto University has not made independent efforts to verify or atone for its role in wartime research. We hope that our petition will precipitate further verification by Kyoto University to look into the legitimacy of the dissertation,” Nishiyama added.The Kwantung Army was part of the Imperial Japanese Army and stationed in northeastern China, which was under Japanese control.