IRVINE, Calif. — Four people were seriously injured after being struck by a police vehicle in a chain-reaction crash outside a Southern California concert venue.

Irvine police Cmdr. Mike Hallinan says an elderly man driving through the parking lot of the Irvine Meadows Amphitheatre struck a fence, another vehicle and several pedestrians.

He said the car then struck a parked, unoccupied police vehicle, pushing it onto a lawn where it struck several people picnicking before the concert.

Nine people were treated at the scene. Fire officials told the Orange County Register (http://bit.ly/2cjuvw4 ) four who were seriously injured and one with moderate injury were taken to the hospital for treatment.

Hallinan said the cause of the accident was under investigation. There was no indication that the driver was intoxicated.