An illegal fire set by a hunter caused the massive wildfire burning in and around Yosemite National Park, investigators from the U.S. Forest Service announced Thursday morning.

No arrests have been made in the case and the hunter’s name is being withheld “pending further investigation,” the Forest Service said in a news release.

U.S. Forest Service spokesman Ray Mooney said he didn’t know if the fire was a campfire, where the hunter was from or if he was with other hunters.

There is no indication the hunter was involved with illegal marijuana cultivation, Forest Service officials said.

The Rim Fire, which is now 80 percent contained, has burned 237,341 acres, or nearly 371 square miles, including 66,155 acres within Yosemite National Park. It is the largest fire in recorded history in the Sierra Nevada range and the largest fire to burn in Yosemite park since records were first kept in 1930.

The fire is expected to be contained Sept. 20.

The fire began at about 3 p.m. Aug. 17 in the Stanislaus National Forest near Groveland, Calif., in a remote area called Jawbone Ridge.

The vast forest has been the site of illegal marijuana plantations in recent years, and police have removed hundreds of thousands of marijuana plants and made several arrests.

On Aug. 23, a local fire chief, Todd McNeal of the Twain Harte fire department, told a community meeting: “We know it’s human caused. There was no lightning in the area,” and added that it was “highly suspect that there might have been some sort of illicit grove, a marijuana-grow-type thing.”

On Wednesday, Forest Service spokesman Jerry Snyder said that investigators have not found evidence of an illegal marijuana grow at the location where the fire was believed to have begun.

Federal officials at the National Interagency Fire Center in Boise confirmed on Tuesday that no lightning was detected in the area on Aug. 17, which they determined by using a system of high-tech GPS devices that federal fire agencies use to track lightning strikes.

So far, the fire has cost taxpayers $81 million. At its peak, nearly 5,000 firefighters from around the nation were battling the blaze. The fire has destroyed 11 homes. It has not resulted in any deaths, although there have been five injuries.

Under state and federal law, government authorities can seek to recover costs from people who set fires deliberately or negligently. Often, the people who started the fire do not have the means to pay the massive suppression costs. Sometimes, however, they do.

Singer Johnny Cash, for instance, was blamed for starting a fire in Los Padres National Forest in 1965. A camper truck he was driving on a fishing trip near Ventura became stuck in the sand. The hot exhaust pipe touched off grasses and eventually burned 508 acres.

Investigators said he should have done more to put the fire out and should have reported it sooner. Billed $125,000, Cash eventually settled the case for $82,000.

Mormon leaders were found negligent in an August 1989 fire that burned 78 acres of the Tahoe National Forest. It began when officials from the Church of Jesus Christ of Latter-day Saints lost control of a campfire while trying to teach children about fire safety.

The Forest Service bill: $305,000. The church settled for $223,570.

And earlier this year, Pacific Gas & Electric and its contractors agreed to pay $50.5 million to the state Department of Justice to settle allegations that the utility was to blame for two wildfires that burned 18,000 acres in Northern California. Prosecutors alleged that a PG&E contractor dropped a cigarette that caused a 2004 fire that burned 13,000 acres in the El Dorado National Forest, and that the utility’s transmission lines were too close to pine trees, igniting at 2008 fire that burned 5,000 acres in the Mendocino National Forest.