When did the campaign of political  repression that Mikhail Demichev was arrested during occur?
Great Purge The Great Purge or the Great Terror (Russian: Большо́й терро́р ) was a campaign of political repression in the Soviet Union which occurred from 1936 to 1938. It involved a large-scale purge of the Communist Party and government officials, repression of peasants and the Red Army leadership, widespread police surveillance, suspicion of "saboteurs", "counter-revolutionaries", imprisonment, and arbitrary executions. Mobile gas vans were invented to execute people without trial. In Russian historiography, the period of the most intense purge, 1937–1938, is called Yezhovshchina (Russian: Ежовщина ; literally, "Yezhov phenomenon", commonly translated as "times of Yezhov" or "doings of Yezhov"), after Nikolai Yezhov, the head of the Soviet secret police, the NKVD, who was later killed in the purge. It has been estimated that 600,000 people died at the hands of the Soviet government during the Purge.
2006 deportation of Georgians from Russia The 2006 deportation of Georgians from Russia refers to the deaths, unlawful arrests, expulsions and overall mistreatment of several thousand ethnic Georgians by the Russian government during the 2006 Georgian–Russian espionage controversy. The official Russian position was that Georgians in question violated the Russian immigration law and that their expulsion and treatment in custody was just standard law enforcement. The Georgian government countered that Russia's concerted actions against ethnic Georgians, including properly documented individuals, was an act of political retribution for the arrest of Russian spies and was tantamount to "mild form of ethnic cleansing". Georgian claims were supported by the Human Rights Watch, which documented "the Russian government's arbitrary and illegal detention and expulsion of Georgians, including many who legally lived and worked in Russia..." Georgia subsequently sued the Russian Government in the European Court of Human Rights (ECHR).