Elsewhere, federal agents were sent to help local investigators search for evidence in the Orange County foothills where an arson fire has destroyed nine homes.

In San Bernardino County, a man suspected of starting a small fire in the mountains was arrested Wednesday. Another man was arrested Tuesday and still another was shot to death that day by police after he fled officers who approached to see if he might be trying to set a fire.

None of the cases has been connected to any of Southern California's major wildfires, which have scorched about 753 square miles and destroyed about 1,800 homes since late Saturday.

Since the fires began, authorities have stepped up patrols in hopes of preventing copycat fires and looting.

San Diego County officials have reported scattered instances of looting in fire zones and illegal immigrants posing as evacuees to wrangle free food and supplies at Qualcomm Stadium. Drunken drivers and curfew violators have also been arrested in evacuation areas of the fire-scarred San Bernardino Mountains.

The latest arrest came Wednesday after witnesses spotted 41-year-old Catalino Pineda starting a fire on a San Fernando Valley hillside and then walking away, Los Angeles police said.

Witnesses alerted authorities and followed him to a nearby restaurant where police arrested him.

Pineda, a Guatemala native, was booked for investigation of arson and held on $75,000 bail. He's currently on probation for making excessive false emergency reports to law enforcement, police said.

On Tuesday, a motorcyclist who authorities say set a small fire in a rural foothill area of the San Bernardino Mountains was arrested for investigation of arson.