"It was a child-set fire, but it is not clear what his intentions were at this time," said Bill McSweeney , chief of the Los Angeles County sheriff's homeland security department.
McSweeney said the boy was 12, but other media reports said he was 10. The conflicting information could not immediately be clarified.
The boy admitted to starting the fire in north Los Angeles County after arson investigators determined the blaze began Oct. 21 outside his Agua Dulce home. The home was not damaged, said Los Angeles County fire Capt. Michael Brown.
The prosecutor's office was "not sure whether they'll bring any charges, given that it was an accidental fire," Brown said Wednesday.
Prosecutors were set to evaluate evidence in the case as investigators continued to question what started more than 15 major wildfires last week. Downed power lines, arson and construction workers have been blamed with starting five other fires that destroyed some 2,100 homes and blackened 809 square miles (2,095 square kilometers) from Los Angeles County to the Mexican border in the past 10 days.
State Insurance Commissioner Steve Poizner estimated that damage from the fires, most of which were contained by Wednesday afternoon, would exceed $1.5 billion ( EUR 1 billion).
Investigators blamed an arsonist for setting a fire in Orange County that blackened nearly 45 square miles (117 square kilometers) and destroyed 16 homes.
Authorities had sought the driver of a pickup truck spotted in a canyon area around the time the fire broke out. The truck was located and its owners interviewed, but they were not considered arson suspects, said Kris Concepcion, Orange County Fire Authority battalion chief.
Workers using grinding tools on a construction site on Oct. 21 were blamed for a fire near the Magic Mountain theme park in the Santa Clarita Valley that scorched more than 4 square miles (10 square kilometers) over the next few days.
Investigators determined that power lines toppled by the powerful Santa Ana winds were behind a 14-square-mile (36-square-kilometer) fire in San Diego and a 7-square-mile (18-square-kilometer) blaze in Malibu .
A 91-square-mile (236-square-kilometer) blaze in northern Los Angeles County and eastern Ventura County had earlier been listed as fully contained, but officials said Wednesday that containment was actually at 97 percent. A fire in San Bernardino County , east of Los Angeles , was also 97 percent contained.
A mandatory evacuation order was set to be lifted Thursday morning for burned areas near Running Springs and Arrowbear, San Bernardino County fire spokesman Jerry Rohnert said. The Green Valley Lake area was still being assessed.
Across the region, at least 127 evacuees remained in four shelters.
Also Wednesday, Gov. Arnold Schwarzenegger directed state officials to prepare for a new round of possible fires in Southern California as forecasters predicted moderate Santa Ana winds later in the week.
"We are not out of the danger zone yet," Schwarzenegger said at a meeting with the state National Guard, Department of Forestry and Fire Protection and Office of Emergency Services.
State fire officials were deploying firefighting planes and helicopters in fire-prone areas, according to the governor's office. The National Guard also planned to deploy 1,500 Guardsmen and six helicopters to respond to possible flare-ups.
The governor's announcement came amid criticism of state officials after Marine, Navy and National Guard helicopters were grounded because personnel required to be on board were not immediately available.
The Associated Press reported last week National Guard's two newest C-130 cargo planes could not help because they had yet to be outfitted with tanks needed to carry thousands of gallons of fire retardant.
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