CARSON CITY, NEV. ? Fire managers began releasing engines and air power from a fire Saturday that destroyed at least 15 homes as crews secured containment lines near homes and made progress in the Sierra backcountry to keep the flames out of the Lake Tahoe basin.

Meanwhile, officials broadened their investigation of the fire’s cause. They initially said they suspected the blaze was started by teenagers in Kings Canyon the day before the fire erupted Wednesday, but said Saturday the fire could have started last weekend and smoldered undetected for days.

The wind-driven blaze, which scorched nearly 7,600 acres, also destroyed a business and 25 outbuildings. It was 85 percent contained Saturday, and no longer posed an imminent threat to communities in northwest Carson City or surrounding areas in Washoe Valley, officials said.

Fire officials said the blaze could be fully contained by Tuesday with good weather.

“They’re getting a very good handle on it,” fire information officer Mark Struble said at a press briefing. “If we can hold these lines for another 24 hours, it’ll be very, very good.”

Hundreds of evacuees were allowed back home late Friday, but some of them on Saturday questioned whether firefighters could have done more to stop the blaze in its early stages.

“This atrocity should never have happened,” Washoe Valley resident Betty Kelly said at a town hall meeting Saturday. “There was too much waiting and seeing.”

Bill Bettridge, whose home in the Kings Canyon area was spared, suggested fire managers provide the community with a timeline on what action was taken when the pre-dawn fire was reported Wednesday.

Fire officials defended their response, as did some residents.

U.S. Forest Service firefighter Wesley Husted attacks flames along Placerita Canyon Road east of Santa Clarita, Calif. The brush fire started Saturday near the 5 and 14 freeways in Los Angeles and spread into the Angeles National Forest east of Santa Clarita.

“They moved so fast to try to control it,” said Mike Gutter, who watched the fire unfold from her home near Kings Canyon. But the afternoon wind “flattened it out like a pancake and spread it in all directions.”

Gusty winds out of the west pushed the wildfire in different directions. Fueled by trees and brush brittle by five years of drought, the fire swept through the area unlike any seen in Carson City’s history, officials said.

Nearly 2,000 firefighters remained on the lines Saturday, assisted by more than 120 engines and water tenders, bulldozers and aircraft that included three heavy air tankers.

Meanwhile, in California, hundreds of people were forced to evacuate Saturday when a wildfire broke out in northern Los Angeles County. The 2,100-acre blaze threatened Sand Canyon, a community of more than 100 homes, Placerita Canyon and the Placerita Nature Center.

About 750 firefighters were on the scene, battling the blaze with water-dropping helicopters. No homes or structures had been destroyed, officials said.