erm this happened quite a lot
I dont want to disappoint you, or disrupt any cosy thought that all war crimminals were hunted down with equal enthusiasm
Perhaps if you read a bit about the chaos of the end of the war you may get a better idea. War with Russia was regarded as inevitable and wouuld probably break out 1951-1952. this meant that anyone with good anti communist credentials had a value, and could bargain it against their evil Nazi past.
Gehlen organisation sort of wholesale was given immunity and passes to Freedom.
IN Japan, the CIA wanted the information that those evil imperialists had gained by biological research on indians, chinese and caucasians - that is American POWs.
So for example they were staked out - yes really - and sprayed with small pox and so on
these papers were released a few years ago
and people pointed out taht the results on caucasians/Europeans were American POWs
The Japanese were neever prosecuted.
Some Americans were being goofy on a tour of CHina I was on. And were going, Harbin, well where was that, and who was Harbin and so on. I said
Harbin is in Manchuria and is the place that the Japanese did germ warfare experiments on American POWs. The CIA got the info by giving immunity to the Japanese
and they went, oo what's he on about, is this the Korean War (No the Japanese were on your side that time), well where IS harbin and so on and so on.