A vehicle went off the road and through a guardrail, coming to rest next to a river channel in La Palma Saturday evening, according to the Orange County Fire Authority.
Rescue crews were searching for people in the river next to the overturned car at 7 p.m.
The LA County swift water rescue team was assisting at the accident on Walker Street north of the 91 Freeway.
Thirty firefighters were also on scene to aid in the search.
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The search was called off at 8:45 p.m. after searching for an hour and finding no one.
Officials said that the car itself never went into the channel, but the guardrail did.
It wasn't clear who owned the car or what led to the crash.