In an August 2008 issue of the Japanese newsweekly Shukan Gendai, Waseda University professor Toshimitsu Shigemura, an authority on the Korean Peninsula,[46] claimed that Kim Jong-il died in late 2003 and had been replaced in public appearances by one or more stand-ins previously employed to protect him from assassination attempts.[47] In a subsequent best-selling book, The True Character of Kim Jong-il, Shigemura cited apparently un-named people close to Kim's family along with Japanese and South Korean intelligence sources, claiming they confirmed Kim's diabetes took a turn for the worse early in 2000 and from then until his supposed death three and a half years later he was confined to a wheelchair. Shigemura moreover claimed a voiceprint analysis of Kim speaking in 2004 did not match a known earlier recording. It was also noted that Kim Jong-il did not appear in public for the Olympic torch ceremony in Pyongyang on 28 April 2008. The question had reportedly "baffled foreign intelligence agencies for years."[48]

On 9 September 2008, various sources reported that after he did not show up that day for a military parade celebrating North Korea's 60th anniversary, US intelligence agencies believed Kim might be "gravely ill" after having suffered a stroke. He had last been seen in public a month earlier.[49][50] A former CIA official said earlier reports of a health crisis were likely to be accurate. North Korean media remained silent on the issue