A 1982 Fingerprint Card Solved a 1978 Murder: How Investigators Named the Man They Say Killed Corina Contreraz

Three days before Christmas in 1978, a school bus driver making an early run east of Billings, Montana, saw something by the side of the road. It was 7:15 in the morning. It was the body of a 16-year-old girl.

Her name was Corina Lydia Contreraz. Her cousins remember her as petite, a little over five feet tall, and as “kind and fun and loving.” For almost 48 years, her family did not know who killed her. Now, investigators say they do, and the answer came from a place nobody thought to look: an old ink fingerprint card sitting in a file.

The Crime That Haunted Yellowstone County

According to KTVQ, Corina was found near the intersection of Pryor Creek Road and Indian Creek Road east of Billings, not far from Interstate 90. Investigators said she had been sexually assaulted and stabbed 18 times. No murder weapon was ever recovered.

Investigators did one thing in 1978 that would matter decades later. They preserved biological evidence from the scene, even though the technology to make use of it did not yet exist.

Over the next four decades, roughly 200 investigators worked the case at one point or another, according to the Laurel Outlook. Leads came and went. The family waited.

DNA Without a Name

In 2002, the evidence finally produced a DNA profile. That should have been the breakthrough. It was not. The profile was run through criminal DNA databases and came back with no match, according to Cowboy State Daily. Whoever left it had never been entered into the system.

That is a frustrating reality of many cold cases. Having the killer’s DNA is not the same as knowing who the killer is.

Criminal DNA databases only hold profiles from people who have been required to give a sample, usually after an arrest or conviction, and most of those programs did not exist until the 1990s or later. A man who was arrested in the early 1980s and died in 1990 would likely never have been swabbed. His DNA could sit in an evidence locker for decades, searchable but invisible, with no name attached.

In 2012, then-Sheriff Mike Linder formed a dedicated cold case unit. It is now led by Monty Wallis, a retired reserve deputy. The unit kept the Contreraz file open and kept looking for a new way in.

How Genetic Genealogy Narrowed the Search

The new way in arrived in 2023. The sheriff’s office worked with Parabon NanoLabs, a Virginia company that specializes in forensic genetic genealogy. The method compares crime scene DNA against people who have voluntarily uploaded their DNA to genealogy databases, then builds family trees to find where the unknown person fits.

It is the same approach that has cracked a string of decades-old cases across the country, including the 1979 California killing tied to a man who once passed a lie detector test and Boise’s long-unidentified “Unknown Wanderer”.

Investigators identified relatives of the person they were looking for, including a brother, according to the Laurel Outlook. By December 2024, the search had narrowed to one man: Angelo James Stallsmith Sr.

Stallsmith is believed to have been 29 at the time of the murder, according to KTVQ. He died in 1990 at Billings Deaconess Hospital at age 41.

That created a hard problem. Genealogy can point investigators toward a person. It does not, by itself, confirm a match. To be sure, they needed Stallsmith’s own DNA. And Stallsmith had been dead for more than 30 years.

The Fingerprint Card That Closed the Case

In May 2025, investigators located something useful: booking fingerprint cards from a 1982 arrest of Stallsmith. Public reports have not said what that arrest was for.

A booking card is the old-school paper record police made when someone was arrested. An officer would roll each of the person’s fingers in ink and press them onto the card. That means the person’s own skin touched the paper, and skin leaves behind cells.

Forensic scientist Suzanna Ryan of Borealis Forensics took on the job of getting DNA off five of those 1982 cards, according to Cowboy State Daily. She used two approaches. One was a careful scalpel extraction from a thumbprint. The other was an organic phenol-chloroform method, swabbing multiple prints to pull out whatever genetic material remained after more than 40 years.

One card gave her a usable DNA profile. It matched the evidence preserved from the 1978 crime scene.

“We know he touched it, even though the card I worked on was from 1982, so even that many years later that DNA was still present,” an investigator told KTVQ.

Ryan told Cowboy State Daily that, to her knowledge, no homicide had ever been closed using DNA lifted from a booking fingerprint card. If that holds up, this small Montana case just added a new tool to every cold case unit in the country.

What Investigators Got Right, Decade After Decade

It is easy to read a story like this and credit the technology. The technology mattered. But the people who handled this case over 48 years made a series of choices that made the ending possible.

They saved the evidence in 1978. Nobody in Yellowstone County that winter knew what DNA testing would become. Someone still packaged and stored the biological evidence properly. Without that, nothing that came later would have worked.

They kept re-testing as science improved. The 2002 profile did not produce a name, but it gave investigators a fixed target. Every new database and every new method could be measured against it.

They built a unit whose only job was the cold files. Busy detectives working fresh cases rarely have time for a file from the 1970s. A dedicated cold case unit, staffed in part by experienced retirees, gave the case steady attention it would not otherwise get.

They went looking for records others might have thrown out. Tracking down a 1982 booking card for a man who died in 1990 is unglamorous work. It is also what closed the case.

From a process standpoint, that is a model worth copying: preserve, retest, assign ownership, and chase every record. None of it requires a big budget. It requires discipline and patience.

Why This Matters Far Beyond Montana

Think about how many old fingerprint cards are sitting in boxes, basements and archives in sheriff’s offices and police departments across America. Millions of people were booked before DNA databases existed. Many of them have since died. Until now, if a suspect was dead and had no living DNA sample on file, investigators often hit a wall.

This case suggests those paper cards may be a genetic record hiding in plain sight. That has big implications for unsolved murders and sexual assaults where genealogy points to someone who died before they could be tested.

It has also already changed policy. According to the Laurel Outlook, the discovery prompted Montana to stop discarding old fingerprint cards. Other states would be wise to look at their own retention rules before more of these records end up in a shredder.

There are fair questions to raise, too. Genetic genealogy depends on people who uploaded their DNA for family research, not for police use, and privacy advocates continue to push for clear limits on how law enforcement taps those databases. Evidence from decades-old paper also raises questions about contamination and handling that any defense attorney would press in a live case. Here, there is no trial, because the man investigators identified is dead. That means the conclusion has not been tested in court, and it never will be. Readers should understand that is the nature of cases like this one.

Closure, at Last, for a Family

The Yellowstone County Sheriff’s Office announced the case closed in late September. Sheriff Kent O’Donnell said, “Our hearts go out to the Contreraz family especially after all these years.”

For Corina’s family, the news is not justice in the courtroom sense. There will be no trial, no sentencing, no chance to face the man investigators say did this. But it is an answer, and after nearly half a century, an answer is worth a lot.

“It’s really nice to have closure. It’s over. We can breathe now,” Gloria Flores, Corina’s first cousin, told the Laurel Outlook.

Bill Contreraz, another cousin, said, “After all these years to finally know who did it… This is amazing that technology can be applied this way.”

Dotty Ramirez, a second cousin, told Cowboy State Daily, “Her spirit is finally free, and we can breathe again.”

It is a reminder of what we wrote about just days ago in the Christy Dawn Myers case in Georgia: cold cases do not close by luck. They close because someone refuses to put the file away. In Billings, a 1978 decision to save evidence, a cold case unit started in 2012, and one forensic scientist willing to try something nobody had tried before all lined up. Corina Contreraz waited almost 48 years. The people working her case made sure she was not forgotten.