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.
Sergei Ogoltsov Sergei Ivanovich Ogoltsov ("Сергей Иванович Огольцов" in Russian; August 29, 1900 – October 26, 1976) was a Russian member of the Soviet NKVD from 1936 until it was reorganized as the MGB in 1946. He served in the MGB until his arrest in 1953. He was the Deputy Director of State Security (MGB) from July 14, 1951 to August 9, 1951. By the time he was arrested in 1953 he had risen to the rank of Lieutenant General in the NKVD. He was released from prison in 1953 after a short arrest and he retired from the MGB. He died in 1976.