The death of which Bolshevik leader triggered the Great Terror throughout the USSR?

Sergei Mironovich Kirov (27 March 1886 – 1 December 1934), was a prominent early Bolshevik leader in the Soviet Union. Kirov rose through the Communist Party ranks to become head of the party organization in Leningrad.

On 1 December 1934, Kirov was shot and killed by a gunman at his offices in the Smolny Institute. Some historians place the blame for his assassination at the hands of Joseph Stalin and believe the NKVD organized his execution, but any evidence for this claim remains lacking. Kirov's death served as one of the pretexts for Stalin's escalation of repression against dissident elements of the Party, culminating in the Great Terror (or Great Purge) of the late 1930s in which many of the Old Bolsheviks were arrested, expelled from the party, and executed. Complicity in Kirov's assassination was a common charge to which the accused confessed in the show trials of the period.