TUSTIN, Calif. -- The construction worker was in a panic. He shouted into his phone.
"There is one guy down! It's a white truck! There are shots fired! ... The guy has a shotgun and I need an ambulance too! There is someone who has been shot."
The frenzied 911 call came from the worker whose foreman was fatally shot in the wide-ranging rampage of a 20-year-old Orange County man who authorities say killed three people before fatally turning the gun on himself.
The worker stayed on the phone with the emergency operator as he chased the suspect himself.
"Hurry up, hurry up, hurry up! I'm gonna follow him," the call said. "Hurry up, he's going to get into the freeway. He's getting into the 55 freeway ... he's going to escape if you don't hurry up!"
Sirens could then be heard in the background.
The call was one of several released by authorities on Wednesday, the day after the shooting spree of 20-year-old Ali Syed, who authorities described as a video game-playing loner who lived with his parents and spent hours holed up in his room.
The first victim, identified Wednesday as Courtney Aoki, 20, of Buena Park, was shot multiple times inside Syed's home.
Authorities don't know her occupation, how she might have known Syed, how she got in the house – or what drove Syed to kill her with a shotgun and then leave a trail of dead and wounded as he stole a series of cars and eventually committed suicide at an intersection.
"There is no evidence, no notes that would explain his very bizarre and violent behavior," Amormino said, adding there was no evidence of a sexual assault and the woman was found fully clothed.
Syed had no criminal history and no history of mental illness or mental disability, said Lt. Paul Garaven, a Tustin police spokesman.
A 12-gauge shotgun used in the killings belonged to Syed and was purchased by his father about a year ago, Amormino said.
Attorney Vincent John LaBarbera Jr. made a statement for Syed's family Wednesday night.
"No words can express their heartbreak and sorrow," La Barbera said. "Their thoughts and prayers go out to the families of all the victims. They will continue to assist authorities in the investigation as they themselves try to make sense of this tragedy."
The shootings and carjackings lasted about an hour and created chaos and terror for early morning commuters who were shot at, had their car stolen or saw someone get shot.
The rampage began before dawn Tuesday at the home in Ladera Ranch, a wealthy Orange County suburb about 50 miles south of Los Angeles, and ended 25 miles to the north during the early morning rush hour.
Syed killed two more people during carjackings, injured at least three more, and shot up cars zooming down a busy freeway interchange before he ended it by putting the shotgun to his own head as police closed in.
An autopsy will determine whether Syed had any drugs in his system, but Amormino said no illegal drugs were found in the house and there were no signs he was using illegal substances.
His parents did not recognize the woman who was shot to death in the Ladera Ranch home, he said.
Syed's parents called police at 4:45 a.m. Tuesday after hearing the gunshots, but Syed had already sped off in their black SUV.
Officials released the 911 call Syed's parents made as a dispatcher tried to elicit information from the shooter's panicked, sobbing mother as a house alarm blared in the background.
"I think somebody was shot," the mother said in her first comprehensible statement. "I heard a gunshot."
From Ladera Ranch, the gunman headed north and pulled off Interstate 5 in Tustin, about 20 miles away, with a flat tire, police said.
There he fired at and wounded a man in a car, then carjacked a vehicle from a man at a gas station and got back on the freeway, where he fired at commuters, authorities said.
The shooter then exited the freeway in nearby Santa Ana and carjacked a BMW, killing driver Melvin Lee Edwards, 69, of Laguna Hills.
Edwards served as a U.S. Army combat infantry officer in Vietnam and graduated from the University of Southern California, according to a biography on his company's website. He and his wife, Cheryl, had celebrated their 42nd anniversary on Feb. 12 and have two adult children, his brother-in-law, Jeff Osborn, told the AP in a phone interview.
"He was an extremely remarkable person. I know it's an old cliche, but he really did love life," he said. "The world's a lot smaller today for not having him here."
One 911 caller told a dispatcher she watched through her rear-view mirror as a man later identified as Edwards got shot and another caller reports that he's can see him lying near the off-ramp.
Syed took Edwards' BMW and next popped up at a Tustin business, where he shot and killed construction worker Jeremy Lewis, 26, of Fullerton. Lewis' co-worker rushed to intervene and was shot in the arm, authorities said.
Syed took the second construction worker's utility truck and fled to Orange.
He jumped from the moving truck at an intersection about five miles away as officers began to follow him and shot himself in the head.
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By GILLIAN FLACCUS 02/21/13 03:39 AM ET EST