TUSTIN, Calif. (AP) -- The link between the gunman in a series of deadly California shootings and the woman police say was his first victim remained a mystery Thursday as detectives struggled to piece together the threads of the bizarre and fast-moving rampage.
Homicide detectives were trying to determine how the shooter, 20-year-old Ali Syed, knew his first victim, a 20-year-old aspiring actress named Courtney Aoki, said Orange County sheriff's spokesman Jim Amormino.
Deputies found Aoki dead of multiple gunshot wounds at 4:45 a.m. Tuesday at the home Syed shared with his parents.
As Syed's parents placed a panicked 911 call, Syed sped away in their black SUV and went on to kill two drivers during carjackings, shoot up cars on a busy freeway interchange and injure at least three others before shooting himself in the head, police said.
Investigators will comb through computer and cellphone records for clues about how Aoki met Syed, how she got to the house and what she did for a living, said Amormino. Syed's parents did not recognize Aoki, he said.
Aoki and her mother lived in several Southern California cities in recent years, according to public records, but she was not living with her mother or attending school at the time she died, Amormino said.
Her mother did not return a message seeking comment.
Police described Syed as a video-game playing loner who was unemployed and lived with his parents in an upscale development in the southern Orange County suburb of Ladera Ranch, about 55 miles southeast of Los Angeles.
He was enrolled in one community college course, an introduction to computer repairs class at Saddleback College.
Syed kept to himself and sat in the back, but was a good student with an affinity for the material, said his instructor, Eugene Evancoe.
"It's a complete surprise to me," he said. "He didn't do anything to raise concern or alarm."
Police have said Syed had no criminal history or history of mental illness and there is no evidence of illegal drug use.
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