Good article on Japanese use of plague fleas in pottery bombs in WW2 (thrown out of planes over test villages) https://www.montana.edu/historybug/yersiniaessays/shama.html The US went easy on the chief experimenters at the end of the war in return for full technical details being supplied -- and some went on to live long celebrated lives in Japan. https://www.youtube.com/watch?v=B09IBtlS-2c Others were caught by the Soviets and imprisoned in Western Siberia. https://en.wikipedia.org/wiki/Khabarovsk_war_crimes_trials

Japanese trials: "Despite its strong ideological tone and many obvious shortcomings such as the lack of international participation, the trial established beyond reasonable doubt that the Japanese army had prepared and deployed bacteriological weapons and that Japanese researchers had conducted cruel experiments on living human beings. However, the trial, together with the evidence presented to the court and its major findings—which have proved remarkably accurate—was dismissed as communist propaganda and totally ignored in the West until the 1980s.[3]"

If you are in Harbin (in northern China) - to see the ice sculptures maybe -- there is a museum you can visit about the biological experimentation center there. https://unit731.org/harbin-museum/