A Los Angeles Police Department officer was also involved in the collision but escaped injury, according to the Los Angeles County Fire Department. Whether the officer was on duty at the time was not immediately clear.
The five-car pileup was reported shortly after 10:30 a.m. at the Las Virgenes Road exit, officials said. Additional details about the victims were not immediately available.
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The California Highway Patrol issued a SigAlert and closed the offramp, resulting in a backup of westbound traffic on the 101.
The cause of the crash is under investigation.