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.
Vladimir Danchev Vladimir Danchev was a newscaster at Soviet radio in Moscow, who is famous for calling on the Afghan people to resist the Soviet invasion of their country on 23 May 1983. His controversial encouragement of armed resistance against the Russian military outraged many of his countrymen. However, according to the American political analyst Noam Chomsky and other commentators, his principal transgression was that he embarrassed the Soviet government by contradicting their official ideology, by describing the presence of Soviet forces in Afghanistan as an “invasion.” According to the party line, Russia was not invading Afghanistan; it was defending the Afghan people against terrorists who were funded by foreign sources (the USSR was referring to the Mujahedin and the CIA). Danchev was subsequently sent to a psychiatric hospital and returned to work in December 1983. He was praised in the U.S. media as a hero of free speech and free thought. Danchev was of Russian and Bulgarian descent and grew up in Tashkent, Uzbek SSR.