Beaten, strangled, burned; her body was left overnight in the parking lot of an Irvine office park.

Nearly seven years later, the two brothers who admit to taking her life have also pleaded not guilty to first-degree murder, saying the killing wasn’t planned.

One of those brothers, Zenaido Baldivia-Guzman, faces retrial after his case was declared a mistrial last week in Santa Ana Superior Court. The second brother, Gabino Baldivia-Guzman, is expected to face trial later this year.

Prosecutors and defense attorneys debate whether the killing legally was first- or second-degree murder, but they don’t debate who was responsible.

But even as justice grinds forward, a mystery remains.

The woman had no ID when she was found. She was left with her clothes and a pair of unusual shoes, but without a driver’s license or bank card or phone. No one who knew her witnessed her death.

And the things she did have, the things we all carry – fingerprints and teeth and DNA – have provided only half of a puzzle. After seven years of relentless and sometimes unusual effort, the street cops, detectives and criminologists working on the case still don’t know who she was.

All of which raises a question: In 2016, when seemingly every public act can be tracked online or on video, when a single keystroke can send our secrets or our faces around the world, how can a woman found dead in a parking lot spend seven years with the name Jane Doe?

LESS THAN A GALLON

John Ring saw her before he could park.

Sept. 5, 2009, was a Saturday, and at 8:30 a.m., the parking lot at Pasternack Enterprises was empty except for Ring. And he was there only because he wanted to catch up on work in his job as vice president of sales and marketing for Pasternack, a military supplier based in the part of Irvine that borders northbound 55.

After he pulled into the lot and saw the woman, facedown and almost certainly dead, Ring was unnerved. He told police that he kept driving for a moment before stopping, a few spaces away, to call 911.

Investigators from Irvine’s fire and police departments arrived within minutes, calling in a description of the body: a woman, early 20s, black, about 6 feet tall and 150 pounds, a single piercing in each ear. Her face was bloody and bruised, her left eye was swollen, and her tongue was protruding.

She also had been burned.

Orange County Fire Authority investigator John Abel determined that she had been set on fire in the parking lot, probably in the same, slightly curled up position she’d been found. Based on the damage to her body and clothes, Abel believed less than a gallon of gasoline was used to set her ablaze, and the fire burned itself out. A crime scene investigator working near the body found, among other things, a blue lighter.

Authorities couldn’t say exactly when she’d been dumped. They knew only that the cleaning crew saw nothing suspicious before they left, between 10:30 p.m. and 11 p.m., about 10 hours before Ring drove up.

So, around midday, the investigators and crime scene techs gathered the few clues they found at the scene, collected what was left of the woman’s outfit – shorts, a top and a pair of high heels – and went off to begin the hunt.

SEARCHING high, LOW

As an obvious homicide, the investigation started with two goals – to find the killer and identify the victim.

On both fronts they had half a clue: The woman in the parking lot had been burned. If the crime scene and the body didn’t generate many leads, maybe the accelerant or the flames it produced would.

Irvine police Detective Vicky Hurtado, who led the investigation, explained to a jury this month that because police had no address for the victim, she told detectives to visit 15 hotels and motels between Santa Ana and Irvine Spectrum. Initially, she said, they pressed the fire angle.

“Anyone who came in smelling of gas, or who had burns on them. … Anyone who left a room in a hurry. Really, anything that could help us identify a suspect or a victim.”

Police also began the tedious process of looking at video taken from a half-dozen businesses, watching about 100 hours of cars pulling into parking lots and people signing documents and walking through hotel and motel lobbies.

After a few days, when the hotel queries came up empty, police expanded the search to gas stations and local hospitals. Had anybody bought gas and taken it away in a can or bucket? Had anybody shown up in an emergency room with burns on his hands? Those questions also led them nowhere.

Soon, investigators printed fliers about the woman in the parking lot, the same tactic a family might use to find a lost pet. They handed them out at medical and social service agencies, at child protection units and mental health offices. They took their message to other police departments and the National Center for Missing & Exploited Children.

They heard nothing.

WHO SHE WASN’T

Investigators did learn one thing about the woman: She’d never been arrested.

As investigators fanned out to hotels and gas stations and other police agencies, technicians at the Orange County Crime Lab sent the woman’s DNA and fingerprints to state and federal databases. But the samples didn’t match anything in those systems, meaning the woman in the parking lot had never been a criminal suspect or perpetrator or, before her death, a victim.

They also learned she grew up without dental care.

With no matches coming from DNA and fingerprints, crime lab techs next focused on the woman’s teeth, hoping to find evidence of dental work that could be traced to a particular dentist and, critically, his or her billing records.

But it appeared she’d never had any dental work, and her dental X-rays did not match any in the Department of Justice database. Her teeth were another dead end.

With little else to go on, investigators turned their focus to the woman’s footwear – a pair of Glaze high heels, size 10.

“The shoes were really the only item of clothing that had a full label we could identify,” Hurtado testified.

Detectives looked up shoe manufacturers. They traced shoe retailers. And, once again, they talked with every store owner and sales associate who might have sold a pair of size 10 heels to a 6-foot-tall woman. But none had.

The investigators also contacted online retailers to see if they had sent any size 10s to anyone who matched a description of the victim. Again, no luck.

They took an unusual step, turning the shoes into the subject of a media campaign.

Within weeks after the body was found, a picture of a pair of size 10 Glaze high heels, black with a metal zipper in the front, manufactured by Elegance Enterprise – plus a police sketch of the woman and contact information for Irvine police – appeared on TV news and in print and online media. The tactic generated several tips but no solid leads.

Investigators even considered a plan to trace her through familial DNA, a rarely used tactic in which DNA is partially matched to biological relatives who might be listed in a state or federal database. That idea was dashed when investigators learned the search could be used only to track down suspects of crimes, not victims.

In all, investigators looked into more than 6,000 missing persons cases. None helped them learn the woman’s name.

THE OTHER HALF

Investigators had more luck on the other side of their hunt.

One clue at the scene was DNA under a fingernail on the woman’s left hand. The DNA had a Y chromosome; it was male.

In November 2010, about 14 months after Ring saw the woman in the parking lot, the male DNA found under her fingernail popped up as a match to Zenaido Baldivia-Guzman, then 24, a Santa Ana auto detailer who recently had been convicted on a charge of domestic violence.

Within hours of being taken into custody, Zenaido Baldivia-Guzman and his older brother, Gabino, confessed to taking part in the woman’s death.

The brothers offered horrific, incriminating detail that matched up with what investigators had discovered.

They said they’d been drinking the night before the body was found and decided to take their work van out to find a woman with whom they could have sex. They described meeting a woman who matched the victim’s description near Harbor Boulevard and First Street in Santa Ana.

Gabino told investigators that he and the woman negotiated a price to have sex and that she got into the van’s passenger seat willingly. But, he added, she began screaming when she realized that Zenaido was behind her, in the back of the van. Zenaido, both brothers said, pulled her into the back of the van and struck her in an attempt to quiet her screaming.

When the tall, strong woman fought back, Zenaido choked her – hard enough to break a bone in her neck and long enough to end her life, prosecutors believe.

Unsure of what to do, the brothers decided to dump the woman in a parking lot they knew near the 55. They’d detailed some cars there and believed the place would be isolated.

Gabino also told police that he was the one who grabbed a can of gas they used for a generator and used it to set the woman’s body on fire.

The brothers knew many things about how the woman spent her last moments, but they didn’t know her name. And, in a final indignity, they told police they tossed her cellphone into a street.

That wiped out one last path to her identification.

NOT ALONE

The woman is No. 16.

That’s how many women are listed as Jane Doe by the Orange County Coroner. Other Jane Does include a woman found decapitated in a Santa Ana park in 1988, a woman whose bones were found in Anaheim in 1987 and a woman found in a field in Huntington Beach in 1968.

While technology is making it harder than it once was, it’s not unheard of to die nameless.

In a typical year, about 4,400 people die in the United States without identification, and about 1,000 of those remain unidentified after a year of searching. In all, about 40,000 human remains have been buried or cremated in the United States without being accurately identified, according to federal statistics.

Some of the unidentified dead are tied to suspected serial killers. Others were trying to start new lives, away from family or friends. Still others died before the advent of DNA identification and other modern investigation techniques.

Experts say modern data tracking prevents most people, particularly adults, from falling through the cracks. But the sheer number of killings and unexplained deaths in the United States also means it’s not uncommon for a person to die – like the woman in the parking lot did – without being identified even as their killers are brought to justice.

“They are the people who maybe no one is looking for,” said Todd Matthews, a director with the National Missing and Unidentified Persons System, sometimes known as NamUs.

Investigators haven’t forgotten the woman in the parking lot. In any homicide, police and prosecutors want to catch the killer and ease the pain of the victim’s family. Without a name, the family can’t be helped.

Zenaido Baldivia-Guzman has offered a message for the woman’s family, wherever they are. A translation of a handwritten letter of apology, written in his native Spanish, includes this:

“I know I took someone so loved. … I do not know how to live with my conscience, because I also have a family.”

The woman in the parking lot eventually was cremated. Her death certificate doesn’t say when that happened. No one who knew her took part in the service.

Contact the writer: semery@ocregister.com