LOS ANGELES (AP) - The climbers were on their way to the top of California's second-highest peak when they came upon the grisly discovery of what looked like a bone buried in a boulder field.
Closer inspection revealed a fractured human skull. Tyler Hofer and his climbing partner moved some rocks aside and discovered an entire skeleton. It appeared to have been there long enough that all that remained were bones, a leather belt and a pair of leather shoes.
The discovery a week ago beneath Mount Williamson unearthed a mystery: Who was the unfortunate hiker? How did he or she die? Did the person have a partner? Were they ever reported injured, dead or missing?
The Inyo County Sheriff's Department doesn't have any of those answers yet but retrieved the remains Wednesday in the hopes of finding the identity and what happened. There's no evidence to suggest foul play, spokeswoman Carma Roper told The Associated Press.
"This is a huge mystery for us," Roper said.
The body was discovered Oct. 7 near a lake in the remote rock-filled bowl between the towering peaks of Mount Tyndall and Williamson, which rises to 14,374 feet (4,381 meters). The pair of climbers who discovered it phoned in their report once they got a cell phone signal and met with the sheriff's department the next day after hiking out, Sgt. Nate Derr said.
Hofer wrote about his "pretty crazy" discovery on Facebook and posted a photo taken next to where the skeleton was found.
"Needless to say, we were a bit shocked," Hofer wrote.
Derr, who coordinates the county's search and rescue team, said bodies found in the mountains are typically connected with someone they know who has gone missing. The opposite is rarer: finding the remains of someone that appears to not have gone missing or reported as missing.
Because the body was so decomposed, investigators believe it's possibly been there for decades.
They have ruled out that it's 1st Lt. Matthew Kraft, a Marine from Connecticut who vanished in February during a nearly 200-mile (320-kilometer) ski trek through the Sierra. Derr also doubts it's Matthew Greene, a Pennsylvania climber last seen in the Mammoth Lakes area - nearly 70 miles (112 kilometers) north - in 2013.
They've gone back through decades of reports of people missing in the Inyo National Forest and come up empty, Derr said. Neighboring Sequoia and Kings Canyon national parks also don't have reports of anyone missing in that area.
The death could have occurred in the days before helicopters were used to fly out bodies, Derr said. It's possible, he said that the person perished on the mountain and was buried by a climbing partner.
Although the mountain is the state's second-highest, it's not summited as frequently as other high Sierra peaks because it is a forbidding approach. The elevation gain from the trailhead in the high desert to the summit is the greatest of any peak in California.
It can take more than a day to hike over Shepherd Pass and then the trail ends and climbers have to make a tedious scramble over rock fields and sand before climbing the final 2,000 feet (600 meters) up a chute that includes moments of breathtaking exposure picking their way up a rock face.