Besides those killed, another 35 people were injured, the San Francisco Chronicle reported. The bus was traveling from Sacramento to the Colusa Casino near Williams when the accident occurred Sunday night.

Officials said the driver, Quienten Joey Watts, 52, of Stockton, Calif., was hospitalized, The Sacramento Bee reported.

The California Highway Patrol said Watts was arrested for suspected DUI, the Chronicle said.

CHP Special Officer Robert Kays told the Bee the bus had Texas license plates and an invalid registration, which hindered officials from determining who owned the vehicle. The Bee said the owner was later determined to be bus line owner Daniel Cobb Sr., 68, of Sacramento, who the Chronicle reported was among those killed.

About 45 people were on the bus and they were "possibly Laotian" from Sacramento, CHP spokeswoman Fran Clader told the Bee.

The crash occurred on a two-lane road that is a shortcut for motorists headed to the casino, officials said.

Kays said witnesses told police they saw the bus swerve onto the right shoulder, over-correct "and it wound up going across the highway, flipping and overturning so it was facing in the wrong direction ... from the original direction it was going."

The Chronicle reported records show Watts had a previous speeding conviction and was involved in a crash two years ago.