Sean Penn mades disheartening discovery on his latest trip to Alaska

Actor Sean Penn made a disheartening discovery on his latest trip to Alaska this summer: Someone had walked off with a pair of boots that had sat in an old bus in the wilderness for almost 15 years.

The bus had become something of a shrine for Christopher McCandless, the subject of Penn's latest movie, "Into the Wild," a young man who died of starvation there in 1992 after four months of trying to live off the land.

McCandless had taken shelter in the bus, which still held pots, pans and other artifacts he left behind after all those years. His boots had remained on director Penn's previous trips to scout locations and film the movie, which opens Friday, starring Emile Hirsch as McCandless.

But two months ago, Penn went camping at the bus site with Jon Krakauer, whose best-seller was the basis for the film.

"Somebody took off their own boots and replaced them with Chris' boots," Penn said in an interview last week at the Toronto International Film Festival, where "Into the Wild" played. "The boots that were left behind were better than Chris," making clear to Penn that the perpetrator was not simply looking to upgrade his footwear.

"I can't help but think it was related to some of the imminent discussion about the movie coming, and somebody hungering to have an eBay item," Penn said.

McCandless' story made national headlines, prompting both sympathy for his experiment in self-denial and criticism that he brought his fate on himself for trekking ill-equipped and ill-prepared into a harsh land.

His death followed a two-year trek around North America in which McCandless sought to divest himself of the trappings of the material world and live life at its simplest.