Witnesses said family members were put in handcuffs as they tried to identify relatives who were hit by the vehicle.
They said the sheriff's deputy was driving fast and without his sirens on when he struck two pedestrians.
"That's just sad because that cop didn't even turn on his lights or nothing. He was going 60 down the road when he hit those people. And he didn't even have his lights on," said witness Sherry Bowden.
Police say 24-year-old Daniel Hiler and 30-year-old Chrystal Jolley were walking a motorcycle across the street when the accident happen.
The California Highway Patrol is investigating.