California Highway Patrol officials detained a suspect who they believe ignited a brush fire Monday that had charred approximately five acres in the Angeles National Forest.

Firefighters from the U.S. Forest Service were dispatched to the fire on East Fork Road, one mile north of Glendora Mountain Road, at 7:53 a.m., according to USFS spokesman Andrew Mitchell.

Los Angeles County firefighters, including 110 firefighters on the ground and in the air with water-dropping helicopters, were dispatched to the scene at 7:56 a.m., according to a county fire department dispatcher.

"They'll probably declare a knockdown time in the next hour or so," Mitchell said at around 9:30 a.m.

The CHP reported at 9:02 a.m. that a suspect was detained on suspicion of starting the fire.