The fire has burned 1,325 acres and is 25% contained, Los Angeles Fire Department (LAFD) officials said Monday evening, up from 0% containment in the morning.
One firefighter suffered a minor injury to his eye, fire officials said. No structures have burned.
Some drizzly rain in the area and an inversion layer have helped prevent the fire from spreading, the mayor said earlier. That marine layer tends to trap heat, and Garcetti warned that once the clouds lift, typically in the afternoon, flames have the potential to take off rapidly.
The arson suspect, a man, is receiving medical treatment for smoke inhalation.
The LAFD had previously said there was a “suspicious start” to the fire, and on Saturday briefly detained and then released a different person. Fire Chief Ralph Terrazas expressed confidence Monday they had the correct suspect now in custody.
“It is an active investigation,” he said. “I can’t give you more details than that, but the person in custody — we feel we have the right person.”
Gusty winds expected in the coming days
More than 500 firefighters are combating the flames in a challenging canyon terrain that’s filled with 20-30 foot brush that hasn’t burned in about 75 years, Garcetti said.
Crews on three fixed wing aircraft and multiple helicopters were battling the suspected arson blaze, officials said.
Roughly 300 firefighters battled the blaze over the weekend, Ortiz said.
“There’s a lot of dense, thick material there, oily plants that have dried out because of the drought,” Ortiz said Sunday. “So, that’s our objective today: to try to keep it out of that and protect the communities and neighborhoods that are to the west of this fire because that’s what’s closest to it.”
Those drought conditions, coupled with the gusty winds the area is expected to see in the coming days, will likely pose some of the biggest challenges in containing the fire.
CNN’s Paul Vercammen, Jon Passantino, Hollie Silverman, Andy Rose, Alaa Elassar and Jenn Selva contributed to this report.