The circumstances surrounding the death last weekend of Kim Jong Il — North Korea's cruel, enigmatic ruler — are turning out to be as mysterious as the details surrounding the secretive dictator's life. South Korea's top spy is refuting North Korea's official account of Kim's death, arguing that details are being revised to make the late "Dear Leader" look more noble. How did he really die? Here, a guide to the mystery:

What's the official account of his death?
On Monday, a news broadcaster announced on North Korean state television that Kim Jong Il had suffered a heart attack and passed away at 8:30 a.m. Saturday morning. Kim had reportedly been traveling on a moving train during an inspection and "field guidance" tour of the country, and the heart attack was brought on by the "great mental and physical strain" of the trip. State media also reported that an autopsy performed the next day "fully confirmed" this diagnosis.

And that may not be true?
South Korean intelligence officials are casting doubts on Pyongyang's story, says John M. Glionna at the Los Angeles Times. According to Won Sei-hoon, "South Korea's top spy," satellite photographs of the Pyongyang train station reveal that Kim's train was actually stationary at the time of the leader's reported death, not traveling through the country as reported. "There were no signs the train ever moved," Won says. Some South Koreans believe Kim simply died in bed at his Pyongyang residence, likely from natural causes. Plus, an ill Kim would probably not have been able to leave his house at all that Saturday, as it was a frigid 10 degrees Fahrenheit that morning, says Tania Branigan at the U.K.'s Guardian. And if he wasn't sick, Kim wouldn't "be up so early, given that he was known to be a night owl."

Does anyone suspect foul play?
Yes. Some South Koreans believe Kim may have been murdered, says Peter Goodspeed at Canada's National Post. For instance, the Korea Times, quoting a political scientist named An Chan-il, speculates that someone within the North Korean government may have killed Kim. Many officials were disgruntled over the naming last year of Kim Jong Un as his father's successor. Military leaders "could have held deep resentment about Kim and North Korea's next leader," An says, and "I would not rule out the possibility that some military officers, who believed their clout and influence had been damaged, could have played a role in his death."

Why would North Korean officials lie?
The image of a "sickly, weakened and prone 'Dear Leader' taking his last breaths may not have sounded sufficiently patriotic to suit Pyongyang's propaganda machine," says Glionna. So perhaps North Korean officials "pulled a page from Hollywood and… did a rewrite."

Sources: Christian Science Monitor, Guardian, LA Times, National Post, Telegraph