Corona, 22, died within minutes of arriving at the scene of a three-car accident.
He says the family is not angry. "There are a limited number of police officers but mutual aid has been called in".
Another witness, Shaun Kingston, said he heard at least 10 gunshots.
Their harrowing tales came as authorities continued to investigate why the gunman opened fire.
As Corona was treated for multiple gunshot wounds including one to her neck, the suspect fled the scene, heading south on C Street toward Third Street and apparently circling the block before returning to his house at 501 E St. Her father, Merced Corona, served 26 years as a Colusa County Sheriff's deputy, the Beereported.
"We're speculating that she never even saw him", Pytel said. She had only been patrolling solo for about two weeks, the chief said.
The suspect - described only as a white male in his 20s - had no prior criminal record or history of violence, according to police officials who spoke at the news conference.
One of the drivers in the crash, Christian Pascual, 25, said the shooter appeared to have been a bystander who fired from behind him. The chief said as police began to surround it, he stepped outside wearing a bulletproof vest.
"I don't remember her talking about anything else than wanting to become an officer", said Gomez, who said her cousin was an athletic star in high school, excelling in volleyball, basketball and track.
"I was sitting on my couch last night and I heard the sirens go by and I thought, this is Davis, it's a minor deal", he said.
"And I said, 'well Natalie, you can do that but you're going to run into people like that all the time. She would come home, she would be beaming", Merced said. "I've known her for a couple of years".
Corona graduated from the Sacramento Police Academy last July and completed her training in December just before Christmas, officials said.
It wasn't immediately clear if the shooter was in the traffic accident or what the motive was.
The suspect was later found dead in a house near the shooting.
Gov. Gavin Newsom said flags at the state Capitol will be flown at half-staff in honor of Natalie Corona. "This is just an absolutely devastating loss to the police department".
She had been on the job just a few weeks. Despite being rushed to UC Davis Medical Center for emergency treatment, she later died from her wounds. Police have not named the suspect, who was found in a house near the shooting, nor determined what prompted the shooting.
"Jennifer and I are terribly saddened to learn of the death of Officer Corona", the governor's statement said. Natalie Corona, 22, was only sworn into her job at the David Police Department last August.
Tributes have been pouring in for a rookie California police officer who was gunned down Thursday night. The Sacramento County Sheriff's Department has taken over as the lead agency in the investigation.