The sprint car that killed his son Saturday went out of control after the steering wheel came off and the car flew off a dirt track in Marysville at 90 mph, Rob Johnson said Monday.
The winged race car flew about 200 feet into the racetrack pit area, where it struck and killed Marcus Johnson, 14, a student at Rincon Valley Middle School in Santa Rosa.
The driver of the car was Marcus' cousin, Chase Johnson, 17, of Penngrove, an experienced racer and a senior at Petaluma High School. He survived the crash.
Rob Johnson, a former racer who owns a Santa Rosa muffler shop, said he was watching the Saturday night event with his sons and other family members.
Before Chase Johnson took the brand new car onto the quarter-mile clay oval track for warm-up laps at Marysville Raceway Park oval, Rob Johnson said he watched Chase secure the steering wheel's quick-release mechanism, a standard procedure.
"I watched him check it," Rob Johnson said, with an emotional catch in his voice.
The elder Johnson said it is a mystery how the steering wheel came loose.
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, the Associated Press reported.
"It's shaping up to look like a mechanical failure, but there's still work to be done," Read said.
Also killed in the crash at about 6 p.m. Saturday was Dale Richard Wondergem Jr., 68, of Grass Valley.