Guards worried
It was Lozgachev's testimony of that night that led Radzinski to speculate about what might really have happened.
The guards slept late the following morning, and so, it seemed, did Stalin - 12 o'clock, one, two o'clock came and no Stalin
The guard confirmed that it was not Stalin who gave the guards the order to go to bed, rather the order was conveyed by the main guard Khrustalev.
"Stalin would taunt the guards by saying 'Want to go to bed?' and stare into our eyes," Lozgachev said. "As if we'd dare! So of course we were glad when we got this order, and went off to bed without thinking twice."
The guards slept late the following morning, and so, it seemed, did Stalin. Twelve o'clock, one, two o'clock came and no Stalin.
The guards began to get worried, but no one dared to go into his rooms. They had no right to disturb Stalin unless invited into his presence personally.
At 6.30 a light came on in Stalin's rooms, and the guards relaxed a little. But by the time 10 o'clock had chimed they were petrified. Lozgachev was finally sent in to check on Stalin.
"I hurried up to him and said 'Comrade Stalin, what's wrong?' He'd, you know, wet himself while he was lying there. He made some incoherent noise, like "Dz dz". His pocketwatch and copy of Pravda were lying on the floor. The watch showed 6.30. That's when it must have happened to him."
'World War III'
The guards rushed to call Stalin's drinking companions, the Politburo. It was their tardiness in responding and calling for medical help that put questions of doubt in Radzinski's mind.
Beria may have been behind Stalin's death
Did they already know too much and so did not need to hurry to the "old man's" side?
Mr Radzinski says Yes. He asserts that Stalin was injected with poison by the guard Khrustalev, under the orders of his master, KGB chief Lavrenty Beria. And what was the reason Stalin was killed?
"All the people who surrounded Stalin understood that Stalin wanted war - the future World War III - and he decided to prepare the country for this war," Mr Radzinski says.
"He said: we have the opportunity to create a communist Europe but we have to hurry. But Beria, Khrushchev, Malenkov and every normal person understood it was terrible to begin a war against America because the country [Russia] had no economy.
"It wasn't a poor but a super-poor country which was destroyed by the German invasion, a country which had no resources but only nuclear weapons.
Those close to Stalin thought he wanted war
"It was the reason for his anti-Semitic campaign, it was a provocation. He wanted an answer from America. And Beria knew Stalin had planned on 5 March to begin the deportation of Jewish people from Moscow."
As always in Russia, conspiracy piles on conspiracy. Some saw buses parked all round Moscow to take away the Jews. Others glimpsed special barns erected for the deportees in Kazakhstan.
But while the drama unfolded over the next few days in Stalin's country house, the citizens of the Soviet Union were split in their reaction to the imminent death of their leader.
Many openly wept for the man they called '"Father", "Teacher", "God". Others in prison camps across the land allowed themselves to exchange secret smiles and hope that things would be different now.
At 9.50pm on 5 March Stalin died. By the next day his body was lying in state in the Hall of Columns, a few streets from Red Square. It is estimated that several millions came to see him one final time. Several hundred were rumoured to have died in the crush.
Fifty years on, the rumours of intrigues and conspiracies continue. For a tyrant like Josef Stalin, a simple death would be just too mundane.
