California 1996 Cold Case Solved – Arrest Shocked Community

On the morning of August 6th, 2020, a man named Don Lingren was doing something he had done countless times before. He was kneeling at his mother’s grave, placing sunflowers in the dirt. His phone rang. On the other end was a detective’s voice he hadn’t heard from in years. A voice that 24 years earlier had told him not to look at his own mother’s body because of what had been done to her face.

 Now, that same detective was calling to say one sentence Don Lingren never thought he’d hear. They had found the man who killed her. But to understand how a case this cold, this brutal, and this quiet for almost a quarter of a century finally cracked open, we have to go back to a firstf floor bedroom in Cavina, California on a January morning in 1996 because what staff found there that day would haunt this community for the next 24 years.

 Mary Francis Lingren was 67 years old in January of 1996. She was a mother of three, her son Dawn, and two daughters, and a grandmother. Her exact date of birth was never made public in the court record, but based on her age at the time of her death, she had likely been born around 1928 or 1929. What we do know with certainty is that Mary Lingren was not a woman who could protect herself.

 7 years before her murder, around 1989, she had suffered a massive stroke. It left her physically weakened, her mobility compromised, her strength gone. This was the reason she was living at the Coina Villa Retirement Home, an assisted living facility in the 800 block of West San Bernardino Road in a firstf floor private bedroom.

 And that detail first floor matters more than it might seem to at first. Her room had a sliding glass door. It opened directly onto the facility’s exterior parking lot. For most residents, this was simply a convenient path to fresh air. For Mary Lindren, a woman who could not run, could not fight, and could barely defend herself against anything more forceful than a strong wind.

 That door was an open seam in an otherwise secure building. It gave anyone standing in that parking lot at any hour of the night a direct line to a sleeping, vulnerable woman. Nobody at Coina Villa knew on the evening of January 18th, 1996 that someone was about to walk through it. Sometime during the late night hours of January 18th or the early morning hours of January 19th, an unknown man crossed that parking lot.

 He approached Mary Lingren’s sliding glass door and he got in. What happened next was reconstructed later through forensic and medical evidence and it is difficult to describe without confronting exactly how brutal it was. Lingren was beaten severely across her head, her face, her entire body.

 She was she was sodomized and she was strangled to death. The beating was so severe that it caused total facial disfigurement. When detectives arrived at the scene the next morning, they made a point of telling her son Don not to look at her. At approximately 7:30 a.m. on Friday, January 19th, 1996, a staff member at Cavina Villa conducted a routine check on Mary Lingren, the kind of check that happens every single day in facilities like this one, usually without incident.

This time, they found her unresponsive in her bed. Paramedics were called. She was pronounced dead at the scene. Within hours, the Cavina Police Department was on site and because of the severity of the crime, they immediately called in the Los Angeles County Sheriff’s Department Homicide Bureau. Among the detectives who responded that morning was a man named Joe Pcell, a name that is going to matter a great deal later in this story because Detective PCEL would spend more of his career on the single case than almost any investigator spends

on any case in their entire life. But in January of 1996, none of them knew that yet. All they knew was that a defenseless stroke disabled grandmother had been murdered in a place that was supposed to be safe and that whoever had done it was still out there. The question every investigator in that building was asking that morning was simple.

 Who did this? And how do we find him? The answer to that question would take 24 years, 6 months, and 18 days. The investigation into Mary Lingren’s murder began with an assumption that made sense on paper. Someone who had access to this facility, someone familiar with its layout and its routines, was probably responsible. So, detectives started close to home.

 They interviewed the facility’s onduty and offduty staff. Administrative employees, nursing staff, maintenance workers. They interviewed the elderly residents living alongside Mary Lingren along with those residents families and regular visitors. They talked to commercial vendors who serviced the building, food delivery drivers, contracted technicians, medical transport drivers, anyone with a legitimate reason to have ever set foot on that property.

 They even canvased the surrounding neighborhood, talking to people living in nearby homes and businesses. Every single one of them was cleared. Meanwhile, back at the crime scene, forensic scientists from the LD crime lab had recovered something critical. biological evidence from Mary Lingren’s body containing foreign genetic material belonging to her attacker.

 From this, lab technicians developed what’s called a single source male STR, short tandem repeat DNA profile. In plain terms, they had captured the killer’s genetic fingerprint. They just didn’t have a name to attach to it. That profile was run through California’s state DNA database known as Cal DNA and through the FBI’s national database, COist, and it came back with nothing. No match.

Detectives widened the net even further, issuing state and national law enforcement broadcasts describing the crime and the offender’s method of operation, hoping another agency somewhere in the country might connect a similar case to a suspect already in custody. Over time, this generated hundreds of individual leads.

 Detectives ran down every single one. Every single one was eliminated, too. Here’s the part of this story that should genuinely unsettle you. There was no investigative failure here. No mishandled evidence, no missed clue, no chain of custody mistake. The detectives did everything right. The problem was something far more frustrating.

 The man who left his DNA at that crime scene had simply never been convicted of a crime serious enough to require his DNA to be entered into any database. He was, as far as the system was concerned, a ghost, and a ghost with no digital fingerprint cannot be caught by a database search, no matter how many times you run it. So, the case went cold.

 Not because anyone stopped looking, but because the only tool capable of identifying this man hadn’t been invented yet. Between 1996 and 2018, the DNA profile from Mary Lingren’s crime scene sat in storage, periodically rechecked against Cotus and Cal DNA as new entries were added year after year. Each time the search came back empty, new offenders were added to the database constantly, but the man who murdered Mary Lingren was never one of them.

 For the Lingren family, this stretch of silence was its own kind of ongoing wound. Don Lingren and his sisters lived through the 1990s, then the 2010s, without the 2010s, without ever getting the phone call they were waiting for. And yet, in one office at the Los Angeles County Sheriff’s Department, someone never stopped thinking about this case.

 In 2009, Detective Joe Purcell, one of the original responding detectives back in 1996, retired from active ali service. But he didn’t leave the department behind. He was rehired specifically as a cold case investigator. And when he came back, Mary Lingren’s file came with him. It stayed on his desk for over a decade.

While the rest of the world moved on, one man kept this case active in his own mind, waiting for the technology to catch up to the evidence sitting in an LD storage vault. That evidence, remarkably, had been preserved in climate controlled conditions for over two decades. Nobody could have known in 1996 exactly how valuable that preservation would turn out to be.

 But it meant that when a new kind of forensic science finally arrived, one capable of doing something COTUS was never designed to do. The sample was still viable, still usable, still waiting. In 2019, that new chapter began. The Los Angeles County District Attorney’s Office through its cold case unit partnered with the least unsolved unit to take a fresh look at Mary Lingren’s file.

 They knew standard database matching had already failed repeatedly for over 20 years. So this time they weren’t going to search for an exact match. They were going to search for a relative to understand what happened next. You need to understand the difference between two kinds of DNA searches because this distinction is the entire reason this case was ever solved.

A standard KOD search looks for a perfect locus for locus match. It’s binary. Either the DNA in the database is the exact same person who left DNA at the crime scene or it isn’t. For 23 years, that search kept returning nothing because the killer’s own DNA had never been entered into any database in the first place.

 Familial DNA searching works differently. Instead of asking, “Is this exact person in our database?” It asks a more creative question. Is anyone in our database closely related to this person? The technology looks for partial genetic matches, patterns that suggest a parent, a child, or a sibling of the unknown suspect might already be sitting in a state offender database for some completely unrelated conviction.

California had built the nation’s first formal policy allowing this kind of search back in 2008, operated through the California Department of Justice, Bureau of Forensic Science, and in 2019, LeD investigators decided it was time to use it on Mary Lingren’s case. The DNA profile recovered from her body in 1996 was submitted to the CAD DOJ for familial DNA searching.

 And then in July of 2020, after 24 years, the California Department of Justice came back with something detectives hadn’t had in over two decades, a lead. The search hadn’t found the killer directly. It had found someone in the state database who appeared to be closely related to him, a kinship match.

 And when investigators traced that family tree, they found an unprofiled male relative living not far away in the city of Elmonte, California. His name was David Adolf Bernal. But a familial match is not proof. It’s a direction. Detectives now had a name, a location, and a theory. But they still needed something no database could give them.

 Bernal’s own DNA collected in a way that would hold up in court without tipping him off that he was under investigation for a murder he might have believed after 24 years no one would ever solve. Here’s where this story takes a turn that feels almost cinematic. Because the way detectives finally confirmed their suspect’s identity didn’t involve a courtroom, a warrant, or an interrogation room.

 It involved trash day, LD investigators began covert surveillance on David Bernal’s residence in Elmonte. They watched him from a distance, documenting his routines, waiting for an opportunity that wouldn’t require alerting him to their presence. And that opportunity came in one of the most mundane moments imaginable.

 Bernal moving his trash recepticles out to the curb. Under a longestablished principle of American law, the Fourth Amendment’s abandonment doctrine, once something is discarded in a publicly accessible place, like trash left out for collection, it’s considered legally abandoned. Law enforcement doesn’t need a warrant to collect it.

Surveillance officers watched Bernal handle those trash cans, and afterward, they retrieved discarded material containing his saliva. That sample went straight to the Lee crime lab for expedited STR extraction. The same type of DNA analysis performed on the crime scene evidence back in 1996. Forensic analysts compared the new profile from Bernal’s saliva against the decades old profile recovered from Mary Lingren’s body. It was a 100% match.

 24 years after Mary Lingren was murdered in a room with a door that didn’t lock properly enough, investigators finally had a name attached to that genetic profile that had been sitting unmatched in storage since 1996. But there’s a detail about the timing of this breakthrough that makes it even more remarkable.

 And it has nothing to do with forensic science at all. It has to do with what was happening to the detective who made it happen. In mid 2020, in the middle of exactly the investigation that was closing in on David Bernol, Los Angeles County made budget cuts that defunded 12 of the 13 cold case detective positions within the LSD homicide bureau.

 Joe Purcell, the same detective who had responded to that first floor bedroom in January 1996, who had kept Mary Lingren’s file on his desk for over a decade after his own retirement, had his formal paid position end on July 1st, 2020. At that exact moment, he was closing in on a suspect. The familial DNA lead had just come back weeks earlier.

 The surveillance on Bernal’s home was either underway or about to begin. And instead of walking away from a case he had carried for 24 years, PCEL kept working it. without pay through July and into August of 2020. He continued the surveillance, coordinated the DNA verification, and helped bring this case to an arrest as an unpaid volunteer on his own former job.

 It’s the kind of detail that sounds almost too dramatic to be true. But it’s documented in the media coverage that followed his work, and it’s part of why this case drew regional and national attention when it finally broke. coverage from KABC TV, CBS Los Angeles, Fox News, and KTVU. The Associated Press, and City News Service reporters, weren’t just covering a cold case getting solved.

 They were covering a man who refused to let a budget line item end an investigation he’d started before some of his colleagues were even born. On August 6th, 2020, that investigation reached its conclusion. Lasted, detectives executed search and arrest warrants at Bernal’s home in Elmonte. He was taken into custody and that same morning while Don Lingren was kneeling at his mother’s grave with sunflowers in his hands, his phone rang with the call he’d been waiting for since 1996.

 But who exactly was the man on the other end of that 24-year manhunt? David Adolf Bernal was born on October 22nd, 1973. At the time, Mary Lingren was murdered in January 1996. He was 22 years old. He had no known prior personal relationship with her. Nothing connecting him to her, her family, or the Coina Villa retirement home in any documented way.

As far as the official record shows, this was not personal. It appears to have been an opportunistic act of predatory violence against a woman he had never met, committed against someone who, because of her stroke, had virtually no ability to fight back. For 24 years, Bernal lived a life that never crossed paths with law enforcement in any way that would have exposed him.

 His absence from Cotus for over two decades confirms that he was never convicted of a crime serious enough to require his DNA to be entered into the system. He simply existed unprofiled until the moment California’s familial DNA program identified a relative of his already sitting in a state database.

 At the time of his arrest in August 2020, he was 46 years old, living in Elmonte, a city just a short distance from where he had committed this crime as a young man. The gap between who he was at 22 and who he had become at 46 is not something covered in any official release. What is documented is only this.

 For nearly a quarter century, he had gone about his life while one detective in Los Angeles County refused to close the file. On August 7th, 2020, one day after his arrest, the Los Angeles County District Attorney’s Office formally filed charges against David Bernal under case number BA489132. He was charged with one count of first-degree murder.

 But prosecutors, led by Deputy District Attorney Beth Silverman of the DA’s Major Crimes Division Cold Case Unit, didn’t stop there. They added three special circumstance allegations. Murder committed during the commission of force, murder committed during the commission of forcible sodomy, and murder committed during the commission of burglary.

 Under California law, special circumstance allegations elevate a first-degree murder charge into capital territory. Bernal was now facing the possibility of life imprisonment without the possibility of parole or the death penalty. His initial arraignment took place in department 30 of the False Criminal Justice Center in downtown Los Angeles with bail set at $2 million.

 The case then moved toward a Los Angeles County grand jury rather than proceeding through a standard public preliminary hearing. On January 26th, 2023, that grand jury returned a superseding indictment against Bernal on the special circumstance murder charges. He appeared in court that same day and entered a plea of not guilty.

 His bail was revoked entirely and he was remanded into custody to await trial. a trial whose outcome, as of the most recent public record, remains pending. For the Lingren family, the arrest alone represented something they had waited nearly 25 years to hear. Don Lingren and his sisters had stayed in contact with Detective PCEL across two full decades through years when there was nothing new to report and no reason to believe the case would ever move again.

 When the arrest finally came, the family released a public statement expressing their gratitude to law enforcement and their relief that after all that time, justice would finally be pursued in a courtroom. What makes the Mary Lingren case so haunting isn’t just a brutality of what happened to her in that first fourbedroom in January 1996.

 It’s everything that had to align decades later to finally answer the question of who did it. A piece of evidence preserved for 24 years in a climate controlled vault. a forensic technology that didn’t even exist when the crime was committed. A detective who kept a case file on his desk for over a decade after his own retirement and who ultimately worked without pay to see it through to an arrest.

 And in the end, something as ordinary as a trash can left out at the curb on a summer morning in Elmonte. This case also stands as a case study in something bigger than one crime. The way American forensic science has quietly transformed over the past three decades. In 1996, a DNA profile with no match in the system was effectively a dead end.

 By 2020, that same profile, untouched, unmatched, but perfectly preserved, became the key that unlocked a familial trail leading straight to a name. Mary Lindren’s case didn’t stay unsolved because anyone failed her. It stayed unsolved because the science hadn’t caught up yet. And when it finally did, there was still one detective standing there ready to use it.

 If a piece of preserved evidence and a technology that didn’t exist yet were enough to crack a case that sat cold for 24 years, you have to wonder how many other unsolved murders are sitting in evidence lockers right now, waiting for the same breakthrough. I’ve covered another case where investigators use this exact kind of familial DNA search to finally identify a killer decades later.

 If you want to see how that one unfolded, that video is right here waiting for you next.