The California Highway Patrol says the FedEx truck driver involved in a deadly crash involving a tour bus full of students in 2014 caused the fiery wreck.
Investigators said the truck driver, travelling south on Interstate 5, drifted into the fast lane, through the median and crossed into oncoming traffic for unknown reasons. The truck crashed head-on with a tour bus bound for Humboldt State University, killing 10 people.
The truck driver, 32-year-old Tim Evans, of Elk Grove, was among the dead. Six Southern California high school students and three chaperones were also killed.
Investigators say fatigue or an unknown medical condition could have led Evans to drift into traffic.