A boot melting out of the ice – a sight that caught photographer and filmmaker Jimmy Chin’s attention. Upon giving it a close look, Jimmy and team discovered a foot, remains that they believe belong to Andrew Comyn Irvine, fondly known as Sandy, who disappeared 100 years ago with the famed climber George Mallory.

“I lifted up the sock and there’s a red label that has A.C. IRVINE stitched into it,” Chin said, describing the moment, reported National Geographic in an exclusive piece.

In September, in the Central Rongbuk Glacier, below the north face of Mount Everest, a National Geographic documentary team including photographer and director Jimmy Chin and filmmakers and climbers Erich Roepke and Mark Fisher, examined the boot.

100 years ago, on the morning of June 8, 1924, Andrew Comyn Irvine, 22, and George Mallory set off for the summit. Mallory’s remains were located in 1999, while the whereabouts of Irvine’s were unknown.

However, the discovery of a boot now could solve the mystery behind what happened on the summit a century ago. Did the duo make it to the top? If yes, they would have preceded Edmund Hillary and Tibetan mountaineer Tenzing Norgay, who are currently recorded as the first people to reach the summit on May 29, 1953.

“It’s the first real evidence of where Sandy ended up. A lot of theories have been put out there,” said Chin about their discovery.

Back in 1999, when George Mallory’s body was found by the alpinist Conrad Anker, as part of the Mallory and Irvine Research Expedition, it gave certain clues, hinting that the duo completed the summit and were descending when they had a fall.

“His (Mallory’s) dark snow goggles were in his pocket, which led to speculation that the fall could have occurred in the evening as the two had been descending. The photograph of his wife that Mallory had planned to leave on the summit wasn’t with him,” Anker wrote in The Lost Explorer, which he co-authored with David Roberts, as quoted by National Geographic.

According to the exclusive report, Chin shared the news with Irvine’s great-niece Julie Summers, 64, who wrote a 2001 biography of Irvine – Fearless on Everest: The Quest for Sandy Irvine. “I’m regarding it as something close to closure,” she said.

Members of the family have volunteered to share DNA samples to compare with the remains to confirm their identity, reports National Geographic in a piece.