Authorities are searching for witnesses as they investigate a pair of brush fires that forced officials to close the northbound lanes on the 57 Freeway through Diamond Bar Wednesday morning.
A caller reported the first fire about 2:19 a.m. north of Tonner Canyon Road, the California Highway Patrol stated in their traffic incident log.
The witness reported seeing a man in the area wearing blue jeans who had a white scarf around his face, the Los Angeles County Sheriff's Department stated in a news release.
The witness told authorities the man was driving a black sedan.
Also, a caller who identified himself as Jason, told KTLA he saw someone throwing what looked like road flares out of a car while driving on the northbound 57 Freeway between East Lambert Road and Diamond Bar Boulevard.
It was unclear if Jason was the same person who reported the incident to the Sheriff's Department.
Arriving firefighters determined at least two fires had started south of Diamond Bar Boulevard, Los Angeles County Fire Department Supervisor Pickett said.
One fire scorched about 10 acres and the other burned roughly 5 acres, the Fire Department stated in a tweet.
A SigAlert was issued for the northbound side of the 57 Freeway while crews battled the blaze.
Traffic was diverted off the freeway at Tonner Canyon Road, according to the CHP.
Two lanes were reopened to commuters as of 7:20 a.m., the CHP stated.
The fire, which was later dubbed the Lambert Fire, was 100 percent contained as of 8:42 a.m., according to the Fire Department.
Investigators have not officially announced a cause for the fire.
Authorities are asking the public for help in their investigation.
Anyone with information was asked to call the Sheriff's Department at 323-881-7500. Those who wish to remain anonymous can call Crime Stoppers at 800-222-TIPS (8477).
KTLA's Alexandria Hernandez contributed to this report.