It's debatable whether Stalin had any responsibility for the
death of Sergei Kirov at all. Kirov was becoming more popular than
Stalin was, but that alone would not explain Stalin having
complicity in Kirov's murder. In addition, after Kirov's death,
Stalin went on a murder spree himself, calling for the arrests and
executions of many people he thought had any connection, no matter
how remote, to the murderer.