SAN FRANCISCO — Authorities are investigating whether a faulty steering wheel caused a Marysville raceway crash that killed two people, including a Santa Rosa teenager.

Undersheriff Jerry Read of the Yuba County Sheriff's Department said Monday that investigators are looking into witness reports that the detachable steering wheel came off just before 17-year-old Chase Johnson's car careened off the dirt track and crashed into pit row.

Sheriff's officials say 68-year-old race car owner Dale Wondergem of Grass Valley and 14-year-old Marcus Johnson of Santa Rosa were killed by the collision at Marysville Raceway Park, about 40 miles north of Sacramento.

The accident occurred around 6 p.m. Saturday when Chase Johnson and several other drivers were doing warm-up laps on opening day of the California Sprint Car Civil War Series.