From 5:30 a.m. to 5:55 a.m., Tustin police received police reports of shootings in several locations, Tustin police Supervisor Dave Kanoti.
The first call that came in was at Red Hill Avenue and Interstate 5. Police arrived and determined a carjacking had occurred and that victim was uninjured. An innocent bystander who was shot by gunfire was taken to a hospital, Garaven said.
The next call was at State Route 55 and McFadden Avenue. Another carjacking occurred and that victim died, Garaven said.
The last call was about a man with a gun, he said, at Edinger Avenue east of the 55. An officer arrived and found two more victims one dead and the other injured.
Officers located the man and followed him into the city of Orange, Garaven said. "When they tried to stop, he killed himself in the car," Garaven said.
The suspect is a male, although Garaven couldn't confirm his age. He didn't have the sexes of all the victims.
The lieutenant said the gunman succeeded in stealing a vehicle at each carjacking.
"There have been other people coming forward saying they were shot at or their cars were shot at," he said but so far none had reported any serious injury.
The conditions of the wounded victims were unknown.
A spokeswoman for the California Highway Patrol said they didn't have any active crime scenes on the freeway but the southbound 55 McFadden Avenue off-ramp would be closed until further notice.
Tustin is about 35 miles southeast of downtown Los Angeles.
The motive for the shootings is still unclear and it's also unclear if the victims knew each other or the shooter, Amormino said.
"I do not believe any of the victims are related to each other. It might have been a random thing," he said. "We just don't know."
Authorities were processing six crime scenes across the county.
Associated Press Writer Sue Manning in Los Angeles contributed to this report.