(BBC News) A former Soviet agent says he has found evidence that Joseph Stalin spied on Mao Zedong, among others, by analysing excrement to construct psychological portraits.
By the sound of things, it was a top secret and rather smelly experiment.
According to Russian newspaper reports, in the 1940s Stalin's secret police had set up a special department to get its hands on people's faeces.
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The ambitious aim: to analyse samples of foreign leaders' stools.