Joseph Stalin spied on Mao Zedong, among other foreign leaders, by analysing his excrement in a lab, according to a former Soviet agent.
Stalin’s secret police aimed to analyse Chairman Mao by formulating psychological profiles from his excrement in a top secret laboratory, former agent Igor Atamenko told the BBC.
Special toilets were allegedly installed for Mao to use when he visited Moscow for 10 days in 1949.
The toilets were not connected to sewers, but collected his waste in secret boxes to be taken to the lab and studied for varying levels of potassium and amino acids, which were thought to aid psychological profiling.
"For example,” Mr Atamenko said, “if they detected high levels of amino acid Tryptophan, they concluded that person was calm and approachable.”
A deficiency in potassium “was seen as a sign of a nervous disposition and someone with insomnia”.
According to Mr Atamenko, secret police chief Lavrenti Beria - who also managed the Soviet atomic bomb project - was in charge of the lab.
Mao's visit to the Russian capital was described by journalist David Halberstam as “in all ways a disaster,” though it did result in a treaty between the People’s Republic of China and the Soviet Union.
