SUNNYVALE . (AP) — A California motorist told investigators Wednesday that he deliberately drove into a crosswalk in a quiet Silicon Valley suburb, hitting seven people and injuring eight, but did not say why.

Isaiah Joel Peoples, 34, was being held on eight counts of attempted murder as four of the victims remained hospitalized with major injuries. A 13-year-old Sunnyvale girl was in critical condition.

Peoples did not resist arrest after the incident Tuesday night and was talking to investigators, Sunnyvale police Capt. Jim Choi said.

“He did not say why he did it,” Choi said. “He did indicate that it was an intentional act. He did not express any remorse as far as we can tell.”

Peoples’ mother, Leevell Peoples of Sacramento, said she couldn’t imagine any situation in which her mild-mannered son would deliberately crash into innocent people other than something related to the post-traumatic stress disorder she said he experienced after serving as an Army sharpshooter in Iraq.

“Unless the car malfunctioned, he would not have done that. He’s like the perfect, model citizen,” she said. “He’s an Army vet, he’s a good kid, never been arrested. I promise you: It was not deliberate. If anything, it was that Army.”

Isaiah Peoples, an auditor for the Department of Defense in Mountain View, received inpatient treatment for PTSD in 2015, his mother said.

Choi said police were investigating the PTSD report.

He said Peoples kept going after hitting the pedestrians until he struck a tree at high speed.

Six people were taken to hospitals, including the youngest victim, a 9-year-old boy who was treated and released with minor injuries. A 15-year-old boy was treated and released by paramedics.

The crash happened at a major intersection in an area with commercial strip malls that residents described as a quiet California suburb.

Businesses and roads were reopened Wednesday and police tape that had been used to cordon off the area after the crash had been removed.

The only remaining signs of the incident were skid marks on the sidewalk where the car swerved, and a dented tree where it crashed.

Don Draper, 72, said he was waiting in his convertible for the light to turn green when the Toyota zoomed by. Draper said he was enraged and marched over to the car.

“He wasn’t hurt apparently, and he was mumbling over and over again, ‘thank you Jesus, thank you Jesus, thank you Jesus’ again and again,” Draper said. “At this point I realized I had to call 911.”

Other witness statements matched Draper’s recollection that the driver was speeding and drove directly toward the pedestrians without trying to veer away or stop in the city about 50 miles (80 kilometers) south of San Francisco.

Leevell Peoples said her son is well-behaved, treats everyone with respect and attends church on Sundays. He wouldn’t even run a yellow light, she said.

“He basically probably has no friends but the people he works with,” she said. “I’m just hoping the Army stuff wouldn’t have caused this to happen. He doesn’t have any seizures or anything.”

She said her son graduated from Sacramento State University after returning from Iraq in 2007. She said he had “a bad episode” with PTSD about two years ago and has told her that he had been regularly taking medication since then.

Former housemate Chuck Herrera described Isaiah Peoples as quiet — someone who had to be coaxed into going out for drinks or dinner. He said Peoples was polite and kind and sweet to Herrera’s toddler son.

He recalls Peoples “always had a lot of pills” and a cough.

“The guy I met was not someone who you think will hurt someone,” he said. “My guess is something happened.”

The FBI is assisting California officials in the investigation.

Leevell Peoples said the Army forced her son to retire because of PTSD. Pentagon spokeswoman Lt. Col. Carla Gleason confirmed that he retired from the U.S. Army but provided no other details.

Draper said a victim had landed in front of his car, with what appeared to be a bloody head wound.

“I saw a body flying through the air, and one of them was right in front of me,” Draper said. “This woman was about 10 feet off the ground; I can see her feet pointing upward.”