TUSTIN, Calif. — The violence stretched across 25 miles in Orange County and was as brutal as it was fast-moving.
In less than an hour, a 20-year-old student wielding a shotgun killed a woman in his home and two commuters during carjackings early Tuesday, shot up vehicles on a Southern California freeway, and committed suicide as police closed in, authorities said.
One driver was forced from his BMW at a stop sign, marched to a curb, and killed as witnesses watched in horror.
‘‘He was basically executed,’’ Santa Ana police Corporal Anthony Bertagna said. ‘‘There were at least six witnesses.’’
The shooter, Ali Syed, was a part-time student who lived with his parents at the Ladera Ranch residence where the first victim was slain, Tustin police Chief Scott Jordan said.
Orange County sheriff’s spokesman Jim Amormino said the woman killed at the home was in her 20s. She was not identified and was not related to the shooter, he said, adding that it wasn’t known what she was doing at the home.
Syed’s parents fled the home when shots were fired, and reported it, he said.
Jordan said Syed stated to one carjacking victim: ‘‘I don’t want to hurt you. I killed somebody. Today is my last day.’’
Jordan said there was no indication of a motive, but he sought to assure residents that the violence was over.
The violence began at 4:45 a.m., when deputies responded to a call from Ladera Ranch, a sleepy inland town about 55 miles southeast of Los Angeles. They found the woman shot multiple times.
From Ladera Ranch, police said, the gunman headed north and within 30 minutes carjacked a Dodge pickup truck in Tustin, about 20 miles away. The driver was uninjured, but a bystander was hit by gunfire and taken to a hospital.
The suspect then began firing at vehicles in the area where Interstate 5 and State Route 55 connect. One person there suffered a minor injury, Tustin police Lieutenant Paul Garaven said. Two cars were damaged.
When the truck became low on gas, the gunman stopped in Santa Ana, stole the BMW, and killed the driver, Bertagna said.
The victim was identified as Melvin Edwards, 69, of Laguna Hills, who was en route to his Santa Ana business.
The shooter then drove to a Tustin business called Micro Center and carjacked another small truck, killing construction worker Jeremy Lewis, 26, of Fullerton, and wounding another person.
Officers trailed the gunman to Orange, a city about five miles away. As they closed in, the man got out of the vehicle at a busy intersection and shot himself, police said.