A young Natalie Corona would run around the house in police gear and loved watching the show “Cops.” She always knew she wanted to be a police officer, her sister said Friday.

Even before Corona joined the force a few months ago, she posted a Facebook tribute to the men and women who serve and who have died in the line of duty. She didn’t know then how much it would touch the world, her father said.

On Friday, family members, friends and thousands of officers from across the country packed into a memorial service to honor the 22-year-old California rookie who was shot and killed during a routine traffic stop.

Uniformed officers, hats in their white-gloved hands, filled about 8,000 seats at an indoor arena at the University of California, Davis, and overflowed into the aisles. Officers from as far as New York, Chicago and Boston came to honor the young policewoman killed last week in this Northern California college town.

Corona’s slaying has shocked Davis, which prides itself on being a safe, family-friendly community anchored by one of the state’s top universities. The last time a police officer died in the line of duty in Davis was in 1959.

Officers lined walkways on the campus and saluted as family members followed Corona’s casket into the 90-minute service.

Colleagues recalled Corona’s vibrant smile, her enthusiasm, compassion, dedication and a lifelong dream she had of joining law enforcement like her father, who spent 26 years as a Colusa County sheriff’s deputy.

“It was truly in her blood,” Davis Police Chief Darren Pytel said. “I placed a bet that one day she’d be the police chief. I know what it takes, and she had it.”

Looking to her parents in the front row, Pytel said they had raised “an incredible daughter.” He apologized to Merced and Lupe Corona for the shooting that ended her life on Jan. 10.

“You delivered to us the perfect cop. Our commitment to you was to get her home,” the police chief said. “I’m so sorry that we didn’t get her back home to you.”

Corona graduated from the Sacramento Police Academy in July and completed her field training in December. She was assigned to patrol on her own just weeks ago.

On the evening of Jan. 10, there was no apparent danger when Corona responded solo to a three-car crash in downtown Davis, near the university. But as Corona talked to the drivers, gunfire erupted.

Police say Kevin Douglas Limbaugh, 48, was not involved in the crash but rode up on a bicycle and opened fire on Corona without warning. He hit her in the neck and fired more shots as she lay on the ground, reloading at least twice as he fired at passing vehicles, narrowly avoiding wounding others before he walked home.

Limbaugh dropped a backpack that allowed officers to trace him to his house, where he had a brief standoff with police, went back inside and killed himself, authorities said.

Police found two unregistered semiautomatic handguns and a handwritten note on the bed that claimed police had been bombarding him for years with ultrasonic waves and he “can’t live this way anymore.”

“We know who committed this atrocity, but we may never know why,” Pytel said. “So far we have nothing to really explain it.”

During the service, a slideshow of family photos and Corona’s brief professional life played on giant screens. It ended with the image from her 2016 Facebook tribute to law enforcement. The picture showed Corona beaming and wearing a floor-length blue gown as she held a “Thin Blue Line” flag that shows support for officers.

“Little did she know that she and this picture would touch so many lives around the world,” her father said.

In a surprise appearance, musician Billy Ray Cyrus strummed his guitar and sang a song he wrote for soldiers of the Vietnam War, saying “the smile of this beautiful young lady touched my heart.”

Corona’s father said he had tried to get his daughter “Nat” to join the county force where he had worked but she told him she had “found the perfect department in the perfect city.”

“She was so proud to be part of the law enforcement brotherhood,” Merced Corona said. “Today we lay to rest our beloved sister cop.”

The eldest of four girls, Corona was a role model, her sister Jackie said.

“Ever since we were little, we knew Nat would become a police officer one day,” Jackie said, recounting how her sister would “run around the house in police gear” and would watch “Cops.”

Sharing some favorite memories, Jackie said Corona loved to dance, even though she lacked rhythm, and was a perfectionist who didn’t tolerate a wrinkled bedsheet.

“She wanted everything to be perfect, including herself. And boy, in our eyes, was she,” Jackie said, flanked by her two other sisters, Cathy and Cindy.

After the memorial service, bagpipes played as police pallbearers carried Corona’s casket to a white hearse on a road lined with saluting officers. A funeral procession then took the casket from Davis to the town of Arbuckle about 40 miles north, where the Corona family lives.