No.1061
Were either Stalin or Mao assassinated? And what is the story with Lin Bao's death?
No.1064
I've never heard about Mao being assassinated. But the view that Stalin was poisoned is pretty common; in "Molotov Remembers" Molotov said that Beria claimed he "saved" everyone by killing Stalin.
The Chinese account of Lin's death, at least back in the 70s, was that he was fleeing to the USSR after his coup attempt against Mao was discovered. His plane crashed, he died.