An ambulance carrying a patient crashed head-on with a car in Pasadena, California, on Saturday, killing the patient and injuring three other people, police said.
The collision took place about 4 p.m. on Fair Oaks Avenue near Mountain Street, officials with the Pasadena Police Department said.
The ambulance patient, identified only as a 79-year-old man, suffered a head injury in the collision and went into cardiac arrest, police said. He was taken to the hospital, where he died a short time later.
"We don't know exactly what happened inside the cabin of that ambulance that led to that serious injury," Pasadena police Lt. Jesse Carrillo said.
Prior to the crash, the patient was being taken to the hospital for a non-emergency medical appointment, Carrillo said. The ambulance did not have its lights or siren on when the collision occurred.
The LifeLine ambulance driver and another EMT were hospitalized in serious condition, Carrillo said.
A woman behind the wheel of the other car, a Jaguar, suffered a broken ankle.
The cause of the crash was under investigation.
It was just shocking. It's so quiet and all of a sudden that just happened," said neighbor Joselin Cegura.
Drivers were advised to avoid Fair Oaks Avenue between Hammond and Mountain streets as police investigated.
NBC4's Joe Studley contributed to this report.