Deputies sought a person of interest after two fires started early Wednesday along the northbound 57 freeway in Brea and spread across the county line into Diamond Bar.

It took more than six hours to get them fully contained.

The blazes shut down lanes of the 57 freeway as firefighters worked to extinguish the burning brush, according to the California Highway Patrol.

The first fire was reported at 2:18 a.m. on the highway near Lambert Road on-ramp. All lanes and the on-ramp were closed, CHP officials said. Northbound lanes also were closed on the Los Angeles County side at Brea Canyon Road.

The two fires burned about 15 acres total, one burned 10 and the other about 5, according to the Los Angeles County Fire Department. It burned north of Tonner Canyon Road and as far north as Brea Canyon Road, according to the Brea Police Department.

There were no immediate reports of injuries. L.A. County fire officials said no structures were threatened.

Shortly before 5 a.m., authorities said all forward progress of the fire had been stopped. More than 100 firefighters worked the blazes.

At about 7:45 a.m., CHP officers opened up the carpool and one other lane.

Just before 8:45 a.m. fire officials said the fire had been 100 contained. Full containment means a control line has been completed all of the way around the blaze, with firefighters confident the fire won’t jump the line as they work to put out all flames and heat sources.

The cause of the fire is still under investigation, however Los Angeles County sheriff’s deputies were looking into a report of a suspicious person seen near the fires’ origin points, authorities said.

“A witness reported seeing a man with a white scarf around his face wearing blue jeans and driving a black sedan,” sheriff’s officials said in a written statement. No further details were available regarding the man or his possible connection to the fires. “Detectives are requesting the public’s help.”

Investigators stopped short of labeling the person as a suspect, but wanted to track him down so see what information he may be able to provide.

“It was a witness statement. “We’re trying to corroborate it,” Detective Ron Greene of the sheriff’s Arson-Explosives Details, which was summoned to take charge of the investigation.

Detectives from the sheriff’s Arson-Explosives Details were summoned to the scene to handle the investigation.

Anyone with information is urged to contact Detective Greene of the sheriff’s Arson-Explosives Detail at 323-881-7500. Tips may also be submitted anonymously to L.A. Regional Crime Stoppers at 800-222-8477.

Staff writer Brian Day and City News Service contributed to this report.