While the flames still raced through California's Sierra Nevada last year, investigators zeroed in on a deer hunter they had rescued by helicopter an hour after the first report of the wildfire that would become the mountain range's largest in its recorded history.
They pressed the hunter, who said at first he caused a rockslide in a remote corner of the Stanislaus National Forest that sparked the blaze, and then blamed illegal marijuana growers, denying he even took a lighter on his hunting trip, according to a search warrant affidavit.
On Thursday -- nearly a year later -- a grand jury returned a four-count indictment against Keith Matthew Emerald, 32, alleging he started a campfire Aug. 17, 2013 in an area where fires were prohibited, and it spread beyond his control and turned into the massive Rim Fire.
The fire raged for two months across 400 square miles of land including part of Yosemite National Park, threatening thousands of structures, destroying 11 homes and costing more than $125 million to fight.
Investigators said Emerald gave inconsistent and changing versions of what happened during multiple interviews that began almost immediately after he was rescued and stretched over several weeks. Emerald was carrying bow hunting equipment when he was picked up from the Stanislaus National Forest, and rescuers and others who had contact with him initially told investigators he appeared not to understand the gravity of the situation and showed little remorse or interest in the dangerous rescue that had just occurred or the status of the fire, according to the affidavit.
A call to Emerald's attorney, federal public defender Janet Bateman, was not immediately returned.
After multiple interviews and a promise from investigators that they would keep his name out of the media for as long as they could, he acknowledged having a lighter, starting a fire and cooking a meal, according to the affidavit. He burned trash from his backpack, but some of the embers blew uphill and set the brush on fire, he allegedly told investigators in a handwritten statement.
"The terrain was almost vertical, so I physically couldn't put it out," he wrote. "The wind was blowing up the canyon hard enough to almost blow my hat off."
He later recanted, but investigators said a man who drove Emerald to pick up his truck after the fire began said Emerald acknowledged setting a campfire that got out of control.
Emerald, a resident of Columbia, a town in the Sierra Nevada foothills, is also charged with lying to a federal agent. He has not been arrested, and prosecutors said no court date has been set for his arraignment.
Authorities previously said the wildfire was started by an illegal fire set by a hunter, but they withheld the hunter's name pending further investigation. In the affidavit, investigators said Emerald was worried about community retaliation if his name got out.
"The Rim Fire was one of the largest in California history and caused tremendous economic and environmental harm," U.S. Attorney Benjamin Wagner said in a written statement. "While those harms cannot be undone, today we have brought criminal charges relating to the cause of the fire."
The charges were the result of an investigation by the U.S. Forest Service and the Tuolumne County district attorney's office, Wagner said.