DAVIS — Natalie Corona was ambushed. The gunman rode up on a bicycle, inexplicably opened fire, and when Corona collapsed, unloaded his semiautomatic pistol on the young rookie police officer.

The gunman reloaded and then began shooting all around him. He hit a nearby fire truck, a passing bus and a woman’s backpack. Then he chased a firefighter who showed up to the scene — and shot at him, striking the emergency responder’s boot.

That’s the account given by Davis Police Chief Darren Pytel in a news conference on Friday night.

Police still are not releasing the name of the suspect, who they say shot himself to death inside a home he lived in near where the shooting took place at 5th and E streets in downtown Davis.

“This clearly looks to us like an ambush,” Pytel said. “Based on how dark it was, we are speculating that she never even saw him.”

The attack occurred as Corona responded to a three-car crash at around 6:45 p.m. Thursday.

Witnesses told detectives that Corona was returning the involved motorists drivers’ licenses when the man opened fire. Her uniform was outfitted with a body-worn camera, but officials said they are unsure if the shooting was caught on video.

The suspect fled from the scene, prompting a large-scale manhunt by multiple law enforcement agencies.

Pytel said police were able to locate the man’s residence located at 5th and E streets by materials found inside a backpack that was dropped at some point after the shooting.

The man’s roommate later told detectives that the suspect returned to the residence after the shooting — after circling the block at least once while fleeing from police — but did not appear to act out of the ordinary. He even joined his roommate outside to watch police swarm the area searching for the shooter, Pytel said.

When officers finally surrounded the suspect’s residence, the man walked outside wearing a bullet-proof vest before returning inside the home. When he went back outside a second time, he yelled something at officers and was armed with a semiautomatic pistol. Police did not fire their weapons.

After going back inside the house the second and last time, he pushed a couch against the front door and blocked entry with a dead bolt. Officers heard a gunshot inside the home.

Officers navigated a robot inside the residence and found him dead of an apparent self-inflicted gunshot wound to the head.

Detectives have not determined a motive in the attack on Corona. She died hours after the shooting at UC Davis Medical Center in Sacramento.

Police did not immediately provide additional details, pending the ongoing investigation conducted by the Sacramento County Sheriff’s Office. The California Department of Justice is investigating the man’s suicide.

Corona completed her field training just two weeks ago and graduated from the police academy six months ago, officials said.

“What really hits us with Natalie is she started with us as a temp employee,” Pytel said. “She had a personality that was just energizing. She was the most friendly, outgoing, and just wanted to be everybody’s friend —and she was.”

Residents, police officers and local leaders in the college town mourned Corona’s death on Friday, dropping bouquets of flowers at the crime scene and tying blue balloons on the branches of nearby trees.

Sarah Ravani and Lauren Hernandez are San Francisco Chronicle staff writers. Email: sravani@sfchronicle.com and lauren.hernandez@sfchronicle.com