Some witnesses say the truck was on fire before the crash.
The family of one of the victims of the fiery bus crash in Northern California is suing FedEx, alleging that its trucks have a history of catching on fire.
The negligence suit filed by the mother of 17-year-old Jennifer Bonilla asks for $100 million in damages.
Bonilla was one of 10 people killed April 10, when the FedEx truck crashed into a bus of high school students and chaperones headed to a college for a tour.