Almost a century later, Vladimir Lenin's enigmatic death has come under new scrutiny.

It's hard to imagine that Lenin's dead body could be shrouded in mystery--after all, anyone who visits his public mausoleum in Moscow's Red Square can see the corpse their own eyes. For three hours a day, five days a week, the body of the first leader of the Soviet Union is open to public viewing. Visitors don't pay a dime. Lenin lies embalmed in a glass case, wearing a suit, a tie and a neat goatee.

Lenin's brain, incidentally, isn't there in his skull. It's been extracted and sliced into 31,000 pieces, which are now mounted on glass behind closed doors at the Moscow Brain Institute. That brain may come in handy for researchers, now that new questions have arisen as to what really killed Vladimir Lenin.

The communist leader died in 1924, and a rumor that he had died of syphilis came to be widely accepted--especially after the European Journal of Neurology turned the suspicion into a retrospective diagnosis in 2004.

But new research conducted for an annual conference at the University of Maryland has raised doubts. Lenin's autopsy records were reviewed by UCLA neurologist Harry Vinters and Russian historian Lev Lurie. The Bolshevik leader had suffered several strokes shortly before he died in 1924, and these researchers found that syphilis, though it can lead to strokes, isn't likely to have resulted in such a sudden demise for a man who was generally healthy for his age.

Instead, Lenin's death could have been caused by hardened arteries. He passed away at 53, and his father passed away at 54. A family history of arterial problems seems a more likely cause of death than syphilis side effects, noted Vinters.

And the stress couldn't have helped with that. People were always trying to assassinate him, for example, added Vinters.

Then there's the possibility that Josef Stalin himself actually poisoned Lenin. Stalin, who led the Soviet Union after Lenin and had already begun to consolidate power when his predecessor was alive, could have begun to see Lenin as a threat. And poison was a weapon of choice for Stalin, according to Lurie. His assassination of Lenin is not such a far-fetched idea.

The funny thing is that the brain of Lenin still is preserved in Moscow, so we can investigate, said Lurie, according to AP.

In other words, this examination of Lenin's mysterious passing is only just beginning.

Lenin led Russia's October Revolution of 1917, becoming the first leader of the communist Soviet Union.  But since the dissolution of the Soviet Union in 1991, when Russia became a federation and dispensed with its old communist system, Lenin's place in history has been the subject of much debate. Russians have considered removing him from his place of honor in the Red Square and burying his body in a St. Petersburg cemetery. To address this issue, an online survey was launched on the website of Russia's ruling political party, United Russia, in 2011. Most of the Russians who voted favored removing Lenin from the mausoleum.

As leading party member Vladimir Medinsky explained, Lenin is a very controversial figure and his role as the focus of a necropolis at the heart of our country is absurd. [The communists] wanted to create a substitute religion based on Lenin's cult, but they failed. It's time to finish with this.

To this day, however, Lenin remains on public view in Moscow.