A mammoth forest fire that killed two firefighters and has burned more than 147,000 acres was an act of arson, authorities said Thursday as they launched a homicide investigation into the deaths.
Officials said they determined that the largest brush fire in the history of Los Angeles County was the result of arson after investigators examined forensic evidence from scorched landscape off Angeles Crest Highway, north of La Canada Flintridge. The spot is believed to be the source of origin of the Station fire.
A source close to the investigation said investigators found incendiary material near the site. The source, who asked not to be identified because he was not authorized to discuss the matter, would not be more specific or identify the material.
Los Angeles County Sheriff Lee Baca said investigators don't want to release details out of fear it could hurt their ability to find and prosecute an arsonist.
Baca stressed that the homicide probe is still wide open, saying investigators believe the fire was set deliberately by someone intent on triggering a devastating blaze but that there is a possibility it could have been sparked accidentally by a negligent person. Either way, the sheriff said the department could pursue homicide charges.
"If an arsonist did this, everyone should be angry about it," Baca told The Times. "This is one of the most unacceptable crimes."
On Wednesday, authorities cordoned off an area near Mile Marker 29 along Angeles Crest Highway with yellow tape, blocking the highway as investigators searched through the ash under a scorched oak tree using wire mesh sifters. Even Caltrans workers were turned away.
The probe has been complicated somewhat by the fact that fire burned over the point of origin twice, making the collection of evidence difficult, other sources familiar with the investigation told The Times.
The arson announcement came as firefighters made more progress Thursday in containing the fire.
As of 5 p.m. Thursday, the Station fire had burned at least 147,418 acres and was about 38% contained. Firefighters expected to have further information on containment after conducting infrared mapping.
Station fire incident Cmdr. Mike Dietrich said that a thick layer of smoke enveloped much of the area around the southeastern edge of the fire, limiting the use of fixed-wing aircraft and helicopters for water and fire retardant drops on the flames.
Most of the fire's growth Thursday took shape on its eastern flank, Dietrich said, where firefighters battling the blaze faced treacherous conditions, including steep terrain and rolling rocks.
Six members of a New Mexico hot shot crew were hospitalized Thursday afternoon, two with moderate injuries and four more with minor injuries, after what was deemed a hazmat incident at the fire's northeastern edge.
On the western edge of the fire, crews managed to cut a series of breaks to further protect the area around Pacoima Canyon, and Dietrich said that they have between a mile and a mile and a half more line to cut there.
Meanwhile, it appeared that both Mt. Wilson and the nearby Stony Ridge Observatory had escaped the worst.
Fire lines around Mt. Wilson, home to a historic observatory and communications towers, appeared to be holding, Dietrich said. "Crews have made excellent progress the last couple days and we're beginning to reap those benefits."
Still, forest officials were guarded in their optimism. In advance of the Labor Day weekend, they took the additional precaution of temporarily closing a huge southern chunk of the Angeles National Forest, stretching from the Grapevine to the 15 Freeway. Under the order, which went into effect at noon Thursday, anyone violating the closure could be fined or jailed.
Baca said that the fire had wreaked havoc on the lives of so many in Southern California.
"I am angry," he said. "Everyone should be angry. There is an appropriate level of anger here. This fire destroyed half of one of the best natural resources, the Angeles National Forest. It sent thousands from their homes . . . and above all else cost the lives of two heroic firefighters."
Times staff writers Corina Knoll, Louis Sahagun, Ann M. Simmons and Richard Winton contributed to this report.