who ruled the soviet union with sole power in a regime of terror
Rise of Joseph Stalin On 1 December 1934, Sergei Kirov was murdered by Leonid Nikolaev. The death of this popular, high-profile politician shocked Russia, and Stalin used this murder to begin The Great Terror. Within hours of Kirov's death, Stalin declared Grigory Zinoviev and his supporters to be responsible for Kirov's murder.[21] Lev Kamenev and Grigory Zinoviev were arrested and, to escape long prison sentences, confessed to political and moral responsibility for Kirov's murder. In January 1935, Zinoviev was sentenced to 10 years imprisonment, and Kamenev was sentenced to 5 years imprisonment. Stalin sanctioned the formation of troikas for the purpose of extrajudicial punishment.[22] In April 1935, Kamenev's prison sentence was increased by another 5 years, to a total of 10 years imprisonment. Hundreds of oppositionists linked to Kamenev and Zinoviev were arrested and exiled to Siberia.[23][24] In late 1935, Stalin reopened the case. Kamenev and Zinoviev were interrogated again, and the exiled Trotsky was now accused of being the leading mastermind in Kirov's murder.[25] In July 1936, Stalin promised Kamenev and Zinoviev (through NKVD chief, Genrikh Yagoda) that there would be no executions or persecution of their families if they confessed to conspiring with Trotsky.[26] Stalin's promise was soon broken. A few weeks later, after a show trial, Kamenev and Zinoviev were both executed on 25 August 1936.