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."
The dispatcher then asked questions to sort out what happened including whether there was an intruder or if the mother had been shot.
"Yes, there is somebody in our house," the mother said.
After several minutes, Syed's father took the phone and said he believed his son may have gotten in a fight with a friend. The father said Syed left the home and took their car but he and his wife had not entered his son's room to see what happened.
"We were asleep, we heard something, it sounded like a gunshot," he said.
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, Jordan 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.