Kern County fire Capt. Tyler Townsend says firefighters and paramedics with Hall Ambulance Service responded to a call of a woman having a seizure. The woman approached the paramedics with a knife, stole the ambulance and took off. The ambulance crew let her take the vehicle without a fight.
"We preach safety first. They followed the protocol and removed themselves from the situation," said Mark Corum with Hall Ambulance Service.
Witnesses said the ambulance was traveling at 100 mph without turning on the sirens.
The woman crashed the ambulance into a semi-truck in front of the Flying J plaza.
"It was like a bomb went off. That ambulance moved that truck!" witness Charlotte Deese said.
Investigators believe the woman may have intentionally drove into the truck.
The woman and the driver of the semi-truck were pronounced dead at the scene. Their names have not been released.
Truck driver Sal Flores shot video moments after the crash.
"Hug the ones that you love, because, you never know, you might not come back. This could have been me!" Flores said.
The Associated Press contributed to this report.