(ABC News)-- A fiery bus crash that killed 10 people, including five high school students, on a California freeway burst into flames almost immediately in a collision that could be heard up to a quarter-mile away, police said today.
The bus was carrying prospective college students from Los Angeles to Humboldt State University in northern California when it was hit by a FedEx truck that traveled over the median and into the northbound lane Thursday night. Police still don't know what caused the FedEx truck to cross the median.
"Our knowledge of it was that (the fire) was almost immediate, the flames were visible and occupants saw flames in front of bus immediately after impact," Glenn County Sheriff Larry Jones said today.
"This was a horrific collision. The impact was heard throughout the communities. People a quarter of a mile away heard this horrendous impact, and right after that impact there was a tremendous fire with very high temperatures," he said.
Investigators would be looking into whether the crash was caused by some mechanical failure on the FedEx truck, whether the driver fell asleep, whether there was a separate accident in the southbound lanes that caused the FedEx driver to swerve into northbound traffic, as well as other potential causes.
Nine people were killed at the scene of the crash, many of whom were riding in the front of the bus, he said. One victim was airlifted to UC Davis hospital with severe burns, but died at the hospital.
Eight of the victims were students, along with the drivers of the bus and the truck. The driver of the FedEx truck has not been identified.
Police are still trying to identify all of the victims of the collision and are asking family members for dental records.
"We know who got on the buses and those who are unaccounted for that we can possibly identify, but our goal is to have a positive ID, and that's long and arduous process," he said.
More than 30 people were taken to hospitals with injuries, he said.
Authorities pulled the final victim's body from the wreckage around 1 a.m. today, and are still removing both vehicles from the scene and processing them for evidence, he said.
Some of the students in the crash attended Los Angeles Unified School District, school officials said.
Timothy White, chancellor of the California State University system, of which Humboldt is a part, said the students were visiting as part of an outreach program to allow students from California cities to come see the campus and speak with current students.
"The thing that makes this ironic and sad is these are the students California really needs. Many of them are first generation (college students) and students from low-income who have done all the right things and who have had their dreams taken away by this accident," White said.
White said he had visited with surviving students who were undeterred in their plans for college.
Student Jonathan Gutierrez was on the bus, tweeted during the trip.