This is a WTF on the depressing side of things.
I've looked up unit 731. They were a Japanese unit that did things like vivisect people alive after infecting them with disease, removed organs, removed and sometimes replaced limbs to test blood loss, tested numerous biological weapons on civilian populations, blew people up with grenades to test their effects at various distances, starved and dehydrated people to see how long they survived, tested the effects of extreme low and high pressure (apparently sometimes dropping the pressure to the point peoples eyes popped out), and did a metric shitload of other stuff. Very rarely was any of this done with any form of anaesthetic.
And they got away with it. They were granted amnesty so long as they turned over their research.
That's not only terrible, it isn't a surprise. Everyone got up to that kinds of stuff.
However, on the actual Wikipedia article it states that any of the researchers that got caught by the Soviets were actually tried in a war crimes tribunal in 1949. This is from the article:
Until Sanders finally threatened the Japanese with bringing the Soviets into the picture, little information about biological warfare was being shared with the Americans. The Japanese wanted to avoid prosecution under the Soviet legal system, so the next morning after he made his threat, Sanders received a manuscript describing Japan's involvement in biological warfare.
So, the Russians were trying them as war criminals, and to get them to spill the beans, the Americans basically said "
we won't try any of you as war criminals, but if any of you don't squeal, we'll hand you over to the Russians who'll totally do that". And:
The Japanese doctors and army commanders who had perpetrated the Unit 731 experiments received sentences from the Khabarovsk court ranging from two to 25 years in a Siberian labor camp. The U.S. refused to acknowledge the trials, branding them communist propaganda.
However, there is evidence that they did give data to the Russians for leniency, but it was probably to avoid the death penalty.