15 March] 1886 in Urzhum in Vyatka Governorate, Russian Empire, as one of seven children born to Miron Ivanovich Kostrikov and Yekaterina Kuzminichna Kostrikova (née Kazantseva).

Sergei and his sisters were raised for a brief time by their paternal grandmother, Melania Avdeyevna Kostrikova, but she could not afford to take care of them all on her small pension of 3 rubles per month.

After gaining his degree in engineering, Kirov moved to Tomsk, a city in Siberia, where he became a Marxist and joined the Russian Social Democratic Labour Party (RSDLP) in 1904.

After a year in custody, Kirov moved to the Caucasus, where he stayed until the abdication of Tsar Nicholas II after the February Revolution in March 1917.

One account states that he chose the name Kir, the Russian version of Cyrus (from the Greek Kūros), after a Christian martyr in third-century Egypt from an Orthodox calendar of saints' days, and Russifying it by adding an -ov suffix.

[1] Kirov was a loyal supporter of Joseph Stalin, the successor of Vladimir Lenin, and in 1926 was rewarded with command of the Leningrad party organization.

[9] In an alleged example from 1932, Stalin wanted to have Martemyan Ryutin executed for writing an attack on his leadership but Kirov and Sergo Ordzhonikidze talked him out of it.

[10] Alexander Orlov, who defected to the West, listed a series of incidents in which Kirov allegedly clashed with Stalin, based on rumours he must have heard from fellow NKVD officers.

He lived on Kamennoostrovsky Prospekt in a large house, inhabited by all sorts of people, he walked to work, wandered on his own around the streets of the city, took his children for rides in his car and played hide-and-seek with them in the yard ... as if to emphasize that Stalin lived in the Kremlin, with guards, didn't wander the streets or play hide-and-seek with his children, thus underlining the idea that Stalin was afraid of the people, whereas Kirov was not.

[12]At the end of the Communist Party's Seventeenth Congress in February 1934, there is reputed to have been a scandal, when Kirov topped the poll in elections to the Central Committee, and Stalin's acolyte, Lazar Kaganovich ordered a number of ballots be destroyed so that Stalin and Kirov could share top billing.

Various accounts of his life agree that he was an expelled party member and a failed junior functionary, with a murderous grudge and an indifference to his own survival.

[17] Ivan Zaporozhets then allegedly enlisted Nikolayev's friend to contact him, giving him money and a loaded 7.62 mm Nagant M1895 revolver.

[16][19] Given the circumstances of Kirov's death, Alexander Barmine stated that "the negligence of the NKVD in protecting such a high party official was without precedent in the Soviet Union.

"[18] Kirov was cremated and his ashes interred in the Kremlin Wall necropolis in a state funeral, with Stalin and other prominent members of the CPSU personally carrying his coffin.

The Soviet government, led by Stalin, stated that their investigation proved that the assassin was acting on behalf of a secret Zinovievist group.

[20] The hapless Commissar Borisov died the day after Kirov's assassination, allegedly falling from a moving truck while riding with a group of NKVD agents.

A Communist Party communiqué initially reported that Nikolayev had confessed his guilt as an assassin in the pay of a "fascist power," having received money from an unidentified "foreign consul" in Leningrad.

[22] Barmine also claimed that Stalin arranged the murder with the Soviet secret police, the NKVD, who armed Nikolayev and sent him to assassinate Kirov.

He stressed that his statement was based on the testimony of one Comrade Yan Olsky, a former NKVD officer who was demoted after Kirov's murder and transferred to the People's Supply System.

Olsky was of the firm opinion that Medved, Kirov's friend and NKVD security chief of the Leningrad branch, was innocent of the murder.

[28] The last attempt in the Soviet Union to review the Kirov murder case was made by the Politburo Commission headed by Alexander Nikolaevich Yakovlev in 1989.

After two years of investigations, the working team of the Commission concluded that no materials were found to support Stalin's or NKVD's participation in Kirov's murder.

[30] Kirov's assassination became a major event in the history of the Soviet Union because it was used by Stalin to justify Moscow trials and his campaign of terror known as the Great Purge.

[32] This view was confirmed by Anastas Mikoyan's son, who stated that the murder of Kirov had certain similarities to the burning of the Reichstag in Nazi Germany in 1933.

The physical removal of Kirov meant the elimination of a future potential rival for Stalin; the principal objective, as with the fire at the Reichstag, was to manufacture an excuse for repression and control.

"[36] The idea of Stalin's complicity in Kirov's assassination has been backed by Robert Conquest and Amy Knight but challenged by revisionist historians who argued that this theory relies primarily on circumstantial evidence and Khrushchev-era investigations.

[38] Alla Kirilina and Oleg Khlevniuk went as far as to claim that "the conventional narratives are almost entirely myth" because they did not find any orders of assassination in the former Soviet archives.

[42] For many years, a huge granite and bronze statue of Kirov dominated the city of Baku, the capital of Azerbaijan, erected on a hill in 1939.

Yevgenia Kostrikova (1921–1975), who claimed to be Kirov's daughter, was a famous tank company commander and World War II veteran.