A Colorado man died during a search for an alleged $2 million treasure hidden somewhere in the Rocky Mountains, The Denver Post reports. Michael Wayne Sexson, 53, and an unnamed 63-year-old man set out to Dinosaur National Monument last week in search for the treasure of Forrest Fenn—a New Mexico antiquities dealer who disclosed the hidden treasure in his memoir. The two men rented snowmobiles and embarked into the wild on March 18—bringing only limited supplies and Fenn’s book. Lt. Chip McIntyre of the Moffat County Sheriff’s Office also said the men “were not dressed appropriately for the conditions.” At some point, the men ditched the snowmobiles and set out on foot.

Later that day, the individual who rented the men the snowmobiles notified police when they didn’t return. Their truck was found two days later, the snowmobiles were recovered one day after that, and the men were found later that day—about a mile away from the snowmobiles. Sexson was dead when officials arrived, and the 63-year-old was hospitalized but later released. “The survivor said at some point they’d tried to get out of where they were to call 911,” McIntyre said. “They knew they were in a bad situation.”

Sexson’s cause of death is still pending, though it is believed to be an accident. He is at least the fourth person to die in search of Fenn’s hidden treasure. “What happened was tragic,” Fenn told the Post. “My heart and prayers go out to the family and friends.”