Juan Sierra was arrested by Los Angeles police Thursday on a probation violation, but a document obtained by The Times shows he was "caught attempting to start a fire" in the West Hills neighborhood already burning during the Kenneth Fire.

Forward progress has been stopped after a fire sparked near the borders of Los Angeles and Ventura counties on Thursday afternoon, officials said. The Kenneth Fire started around 3:16 p.m. on Victory Boulevard west of Gilmore Street in West Hills,

It has burned 959.7 acres after being active for five hours. Currently, there is no information available on the containment of the fire. The Kenneth Fire is burning in West Hills in Los Angeles County and rapidly spreading.

Firefighters are racing to contain a new wildfire that broke out close to homes in the area of Calabasas and Hidden Hills, northwest of Los Angeles, on Thursday afternoon.

At least 10 people have been killed as a result of the wildfires, the Los Angeles County Department of Medical Examiner said on Thursday.

An arson suspect was arrested Thursday night near the Kenneth Fire area as fire crews continue battling flames burning near homes in Calabasas and West Hills. At around 4:30 p.m., Los Angeles police responded to reports of a man attempting to light a fire in the 21700 block of Ybarra Road in Woodland Hills.

The latest update regarding the Los Angeles County fires reveals that an arson suspect has been detained in Woodland Hills and is being investigated for “purposely starting the Kenneth Fire” in West Hills.