On 1 December 1934, Kirov was shot and killed by Leonid Nikolaev at his offices in the Smolny Institute for unknown reasons; Nikolaev and several suspected accomplices were convicted in a show trial and executed less than 30 days later. Kirov's death was later used as a pretext for Stalin's escalation of political repression in the Soviet Union and the events of the Great Purge, with complicity as a common charge for the condemned in the Moscow Trials. Kirov's assassination is controversial and unsolved, and there is a widespread but unproven belief of complicity of Stalin and the NKVD.