Final answer:
The murder of Kirov, a critic of Stalin's policies, compounded by Stalin's known repressive tactics against dissenters, casts suspicion on Stalin's involvement in Kirov's assassination.
Step-by-step explanation:
The assassination of Sergei Kirov in 1934 was a critical event leading up to the Great Purge orchestrated by Joseph Stalin. Prior to his assassination, Kirov was a high-ranking Soviet politician and his death played a vital role in feeding Stalin's paranoia. There were several factors that put Stalin's involvement under suspicion: Kirov had recently criticized Stalin's policies, indicating potential motives for Stalin wanting him gone. Furthermore, the environment of terror and political repression during Stalin's regime, where many perceived enemies and dissenters were executed or sent to Gulag concentration camps, establishes a background of suspicion towards Stalin's potential role in the murder.