He died Christmas day, just like the USSR.
There has been a rumor that suggests Beria, knowing he was about to become the victim of Stalin's next purge, was the one that poisoned Stalin, reportedly telling the remaining Politburo members, who themselves were about to be killed, "I just saved all of you."
Beria
by Amy KnightWho Killed Kirov?
The Kremlin's Greatest Mystery
by Amy Knight