Investigators are trying to determine what went wrong on a Northern California highway Thursday night, when a delivery truck crossed into oncoming traffic and slammed into a bus carrying prospective college students from Southern California, leaving 10 people dead.
California Highway Patrol officials and other public safety personnel said at a news conference Friday morning that nine people died at the scene of Thursday's crash and a 10th victim died at a hospital. Those killed included five students and five adults who were traveling to Humboldt State University for a campus visit. Thirty-one victims were hospitalized after the crash.
It remained "unclear" whether the FedEx driver had fallen asleep or experienced a mechanical failure on the vehicle, CHP officers said Friday.
The update comes as coroner's officials confirmed the identity of a crash victim -- 26-year-old Arthur Arzola, a Humboldt State University admissions counselor based in Los Angeles.
Jonathan Gutierrez, one of two students at Banning High School in Wilmington who was sitting in the back row, told NBC4 Southern California the impact was sudden, extremely painful and immediately ignited a fire.
“It was just a big bang," Gutierrez said. "I had my eyes closed. I was trying to go to sleep. When I heard it I was just like, 'What just happened?' I didn’t want to believe that we crashed, but it was surreal moment."
The students traveling on the bus were set to visit Humboldt State University for a college tour. The California Highway Patrol officials said Friday that among the dead are three chaperones and the drivers of both vehicles.
Another student on the bus, Karmin Aguilar, spoke with NBC4 about the moments immediately after the crash.
"I looked forward to the bus, and I just see fire," Aguilar said. "Just fire, a ball of fire."
She said everyone started screaming and she "started banging the window to the right. Everybody, like three people were trying to fit through the window at one time."
CHP first reported seven students and the bus driver were killed in the crash, but later revised that figure. Five students and five adults were killed, the agency said Friday morning.
The charter bus collided with a FedEx big rig and white Nissan on Interstate 5 near Orland, Calif., about 5:40 p.m., CHP officials said.
The FedEx truck was heading south when it crossed the center line and hit the northbound bus head-on, causing the bus to erupt into flames, CHP officials said. The reason the FedEx truck crashed or how the Nissan was involved was not clear.
An autopsy will determine whether the driver of the FedEx truck had a medical condition or was deceased before the accident.
The bus belonged to Silverado Stages, a tour bus company based out of San Luis Obispo.
The NBC4 I-Team found that Silverado Stages, one of the largest charter bus companies in California, has a good safety record, though the company had two crashes in the last three months, according to Federal Motor Carrier Safety Administration records. FedEx, however, has been involved in 171 accidents in California -- five of them fatal -- in the last two years, according to safety records.
FedEx could not immediately confirm if the big rig was owned by the company or leased from a sub-contractor.
Nearly 50 people were on board, including the students, a few chaperones and the driver, CHP officials said. The group of students from Los Angeles and Riverside school districts was heading to the University's Spring Preview Day this weekend.
According to the itinerary, the students left LA's Union Station 6 a.m. Thursday and were supposed to arrive at HSU by 7 or 8 p.m. They were scheduled to return to LA Sunday morning. Parents had to complete an authorization form consenting to medical treatment before the students were allowed to board.
LAUSD Superintendent John Deasy said several LAUSD students were on the bus, and at least one student who was injured called to say she was ok.
"We don’t know the exact number of LAUSD students who were on the bus, because this was not an LAUSD field trip," Deasy told NBC4. "The field trip was organized by an outside group to visit Humboldt State."
LAUSD spokesman Tommy Chang confirmed students from Robert F. Kennedy High School and Manual Arts High School were among those on the trip.
A parent told NBC4 her twin daughters, Marisa and Marisol Serrato, are students at Norte Vista High School in Riverside, but they boarded two separate buses because one daughter had signed up for the tour late. Their mother said she couldn't get a hold of the daughter who was aboard and was desperate for information about her condition.
"We love them a lot and we're waiting for them to come back," the twins' younger sister Clara Serrato told NBC4.
Gov. Jerry Brown issued a statement Thursday evening on the deadly crash.
"Anne and I extend our heartfelt and deep sympathies to the families, friends and loved ones of those who died in the tragic accident near Orland this evening," he said. "As we mourn the loss of those who died, we join all Californians in expressing our gratitude for the tireless work of the Red Cross and emergency personnel who responded bravely to this terrible tragedy."
LAUSD administrators were en route to the scene of the crash. Both FedEx and Silverado Stages said they were working with authorities during the investigation.
Parents and family members of students who were on the bus may contact Humboldt University police for more information at 707-826-5555.
Orland is about 480 miles north of Los Angeles, and 150 miles north of San Francisco.
NBC4's Tena Ezzeddine, Robert Kovacik, Jacob Rascon and Gadi Schwartz contributed to this report.