SEOUL-- South Korean intelligence officials are casting doubt on Pyongyang's official story line that Kim Jong Il died of a heart attack while working aboard a moving train Saturday morning.
South Korea's top spy, Won Sei-hoon, told lawmakers in Seoul a review of satellite photographs revealed that Kim's train was stationary at a Pyongyang station at the time North Korean officials say he died, according to media reports.
"There were no signs the train ever moved," South Korean media quoted Won as telling officials.
South Korea's Defense Ministry on Wednesday agreed, questioning the circumstances of the dictator's death.
North Korea watchers speculate that the time and place of Kim's death may be sensitive to North Korean officials as they oversee the transition of power to the late strongman's handpicked successor: his youngest son, Kim Jong Un.
South Korean media reported rumors circulating among national lawmakers that Kim Jong Il actually died in his bed at his Pyongyang residence.
Under this scenario, 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. The image of an indefatigable Kim dying while on a "field guidance tour" better fit the legacy of a dictator who didn't know how to quit.
But there's even more intrigue to Kim's final act.
Many observers here say South Korean -- and even U.S. -- intelligence officials are trying to cover up for a major gaffe: not finding out about the death of one of the world's notorious leaders until two days after the fact.
South Korean media have reported that Seoul officials learned about Kim's death Monday along with the rest of the world -- when it was broadcast on North Korean state television. What's more, about the time the news hit here, South Korean President Lee Myung-bak was reportedly attending a surprise birthday party thrown by aides at the Blue House.
Meanwhile, tens of thousands of mourners packed Pyongyang's main square Wednesday to pay respects to Kim Jong Il as North Korea tightened security in cities and won loyalty pledges from top generals for Kim's son and anointed heir, Kim Jong Un.
Women held handkerchiefs to their faces as they wept and filed past a huge portrait of a smiling Kim Jong Il hanging on the Grand People's Study House, in the spot where a photograph of Kim's father, North Korean founder Kim Il Sung, usually hangs.
The North has declared an 11-day period of mourning that will culminate in his state funeral and a national memorial service next Wednesday and Thursday.
The Associated Press contributed to this report.