LAKEPORT, Calif. - People forced to flee a massive wildfire in mountains north of San Francisco heaped anger Tuesday on a man who authorities believe set the blaze that wiped out several blocks of a small town over the weekend along with 16 smaller fires dating back to last summer.

Even as evacuation orders were lifted for several thousand people in that area, a new fire exploded in mountains east of Los Angeles, forcing evacuation orders for about 4,500 people who live in the mountain resort town of Wrightwood.

The blaze also forced the closure of part of Interstate 15, the main highway between Southern California and Las Vegas.

In less than six hours, the fire had burned 26 square kilometres of drought-parched terrain.

Arson investigators in Northern California said Tuesday they had been building a case against 40-year-old construction worker Damin Anthony Pashilk for more than a year but did not have enough evidence to make an arrest until the weekend blaze ripped through Lower Lake - the latest fire to besiege Lake County.

Nearly a decade ago, Pashilk was an inmate firefighter while serving time on drug possession and firearms charges, according to California corrections department spokeswoman Vicky Waters. He was completing a five-year sentence when he was assigned to fight wildfires for four months in 2007.

Pashilk lived in Clearlake - one of the towns that was evacuated but remained untouched by the fire that was still raging in the tinder-dry countryside of Lake County. In a sign of progress, fire officials lifted many of the evacuation orders in the town Tuesday, allowing about 4,000 residents to return.

Authorities would not discuss any evidence against Pashilk.

The Lower Lake fire destroyed 175 homes, Main Street businesses and other structures in the working-class town.

“What I'd do to him, you don't want to know,” said Butch Cancilla, who saw his neighbour's home catch fire as he fled on Sunday. Cancilla still doesn't know the fate of his own home and spoke at a centre for evacuees set up at a high school.

“A lot of people want to hang him high,” his wife, Jennie, added.

Pashilk has not been implicated in any of the three huge blazes that destroyed more than 1,000 homes in Lake County last summer. Little was known about him, other than his history of drug and driving offences dating back a decade.

“I'm hoping, I'm praying that the man has mental illness - because if it's not mental illness, then it's evil,” said Diana Bundesen, who was at the evacuation centre after fleeing Clearlake.

Authorities said the town was near the site where the fire began.

Neither the California Department of Forestry, which led the investigation that resulted in Pashilk's arrest Monday, nor the Lake County sheriff or district attorney would discuss what led authorities to him.

“Arson investigations are complex and difficult. The evidence standards are stringent,” forestry department spokeswoman Janet Upton said. “They have to build a case that is going to be successful, it's complex.”

An attorney listed as representing Pashilk did not return a call requesting comment. Pashilk is scheduled to be arraigned Wednesday.

In a website posting, the Lake County Sheriff's Office initially said he was arrested on a felony count of starting a fire after having an arson conviction within the past 10 years, but later said that was an error made when booking Pashilk and he had no known prior arson conviction.

Roughly 1,600 firefighters were making progress on the blaze as it burned through wilderness. It was 20 per cent contained.

The Lake County blaze is among a half-dozen large wildfires burning in the state, including one that erupted Tuesday in the mountainous Cajon Pass area east of Los Angeles and quickly grew to about 26 square kilometres. The blaze was burning along Interstate 15.

The fire briefly stopped a freight train on nearby tracks. Television news helicopters showed some property, apparently ranch outbuildings, burning. Aircraft were dumping water on the flames that snaked along ridgetops.

In central California, a wildfire near Lake Nacimiento destroyed 12 structures, damaged others and threatened 200 homes. It was 10 per cent contained after growing to 26 square kilometres and forcing authorities to evacuate some residents by boat.

Along the coast, Highway 1 reopened after a daylong closure for removal of fire-weakened trees north of Big Sur. The fire was started by an illegal campfire on July 22 and had burned more than 305 square kilometres, destroyed 57 homes and led to the death of a man in a bulldozer accident. It was 60 per cent contained but still threatened more than 400 structures.

-----

Associated Press writers Kristin J. Bender in San Francisco, Don Thompson in Sacramento and Robert Jablon in Los Angeles contributed to this report.