A motorcyclist died following a crash on the 57 Freeway in Brea on Saturday afternoon, authorities said.
The crash was first reported about 5:40 p.m. on the northbound 57 Freeway, just north of Imperial Highway, according to California Highway Patrol logs.
Officials were looking into whether the motorcyclist had been involved in a collision with another vehicle or a solo crash, logs show.
Authorities initially shut down all northbound traffic lanes following the crash. The carpool lane had reopened by 6:30 p.m., and the rest of traffic lanes were back up and running by 8 p.m.
This story has been updated to correct the city in which the crash occurred.