Sergei Kirov was a Bolshevik party member and organizer, who was arrested several times for his revolutionary activities before the October Revolution.
In 1929, Stalin as Gen Sec transferred Kirov to Leningrad to head up the Leningrad Bolshevik Organisation.
Kirov was a loyal supporter of Stalin and in 1930 was elected to full membership of Politburo.
While appearing to be a staunch Stalinist, in the 1930s his influence and power began to rival that if Stalin.
Stalin was highly paranoid of being overthrown and losing hi power and by taking out any potential competitor he could remove this issue.
On December 1, 1934, Kirov had entered Leningrad party headquarters to continue a busy day of work.
Kirov entered his office but failed to notice the lack of NKVD guards.
Leonid Nikolayev, a bitter, recently expelled party member was waiting for him in his office.
Nikolayev drew out his Nagant M1895 revolver, the standard issue side-arm for army and police in Tsarist times.
Kirov was shot at point blank range in the back of the neck by Nikolayev, Kirov died instantly.
Nikolayev and his 13 accomplices were shot.
Stalin claimed the assassination was a plot led by Trotsky, Zinoviev and Kamenev to overthrow his government.
Within weeks of Kirov's death, the purges started.
Thousands of party members were arrested in Moscow and Leningrad and shot or sent to forced-labour camps, including Old Bolsheviks.
On February 25, 1956, Nikita Khrushchev made a "Secret Speech" strongly implying Stalin engineered the assassination.