Officially, Stalin suffered a cerebral hemorrhage. However, Lavrentiy Pavlovich Beria, longtime head of the People’s Commissariat for Internal Affairs, or NKVD — the secret police boss who killed so many on Stalin’s orders — is suspected of poisoning Stalin. After the war, Beria had yielded direct control of the NKVD (which became the Ministry of State Security, or MGB) while overseeing general national security affairs. Stalin consciously weakened Beria’s authority and appeared to be preparing a new purge; the former’s earlier political cleansings, highlighted by mass arrests and murders, began with removal and execution of the security chief who managed the previous bloody campaign. Beria was living on borrowed time and knew it.
Since everyone in the leadership likely breathed more freely with Stalin dead, no one was inclined to investigate his passage across the river Styx. A collective leadership emerged. Initially, Georgy Malenkov was first among equals, later to be supplanted by Nikita Khrushchev.
Beria was Minister of Internal Affairs — which absorbed the MGB after Stalin’s death — and first deputy prime minister. Most important, he controlled an army of sorts, armed personnel who could be deployed throughout the capital. And no one was immune to blackmail, intimidation, or arrest — the much feared dawn knock at the door. The only person who previously had held Beria in check was Stalin, the early Bolshevik who had out-maneuvered and murdered most of his one-time revolutionary comrades. Even Leon Trotsky, the legendary Red Army commander who suppressed the Kronstadt rebellion, proved no match for Stalin.