Science

Genetic genealogist helps solve a case in which “a gnat of DNA” was left over from the crime scene

Gabriella Vargas is a self-proclaimed “pink-haired, tattooed mom from California who enjoys woodworking and gardening.” She also happens to be one of the most talented investigative genetic genealogists in the world, according to the investigators who worked with her. When the Roxanne Wood cold murder case, 34, came to light in April 2021, “it was thought to be unsolved prior to my involvement,” Vargas said.

Vargas was confident that she could solve this cold case – and swiftly – eventually bring justice to Roxanne Wood’s family. “48 Hours” correspondent Peter Van Sant takes viewers inside the haunting case “The ‘Unsolvable’ Murder of Roxanne Wood” airs Saturday, November 12 at 10/9c on CBS and streaming on Paramount+ .

Roxanne Wood
In February 1987, Terry Wood came home from a bowling night to find his wife Roxanne, who was dead on the kitchen floor at their home in Niles, Michigan. Detectives say Roxanne was sexually assaulted and had her throat slit. DNA was preserved from the crime scene, but given the technical limitations of the time, there was not enough evidence to charge any suspects. Things got cold.

janet wood


In February 1987, Roxanne Wood and her husband, Terry Wood, went out with friends for a bowling night. Roxanne left the bowling alley early to return home so that she could rest at work in the morning. But then a man entered her house through an open door. He sexually assaulted her, grabbed a knife from Roxanne’s kitchen drawer and slit her throat. Terry returns home 45 minutes after his wife to see Roxanne dead.

Even though witnesses had placed Terry in the bowling alley at the time of the murder, he was immediately considered a suspect.

Investigators found DNA at the scene and a sample was preserved. But given the limitations of the technology in 1987, not much could be done with it. Terry continued to remain under suspicion in the community.

As DNA technology evolved, that sample was finally uploaded to CODIS, a national criminal DNA information repository, in 1999. But no matches were returned from that database. As disappointing as it was, everyone expected the DNA to at least clear Terry when it was tested against him. Result? It was not Terry’s DNA.

After that, the case did not yield any new leads till 2020.

To solve the mystery fast, investigators need a way to quickly search through massive case files. They enlisted a group of Western Michigan University students to digitize about 3,500 pages of reports, notes and information in a searchable database.

Around the same time that the students began crunching the data, investigators decided to test the DNA for one last time. He hired Identifiers International—a company that specializes in genetic genealogy—to examine the small amount of DNA left from the crime scene.

“We found out that, what would I say, there’s an eyebrow of DNA left. About 3% of what we normally use,” said Colleen Fitzpatrick, president and founder of Identifiers. “It was the smallest amount of DNA we had to work with to solve a case.”

Gabriella Vargas
Gabriella Vargas, a Goffin’s cockatoo, pictured with Arie, is a self-proclaimed, “pink-haired, tattooed mom from California who enjoys woodworking and gardening.” She also happens to be one of the most talented investigative genetic genealogists in the world, according to the investigators who worked with her.

CBS News


Identifiers spent about 10 months working with the sample’s production data, but came up empty.

“It really seemed impossible,” Fitzpatrick said.

Then, one day in April 2021, Fitzpatrick was chatting with investigative genetic genealogist Gabriella Vargas, who worked as a consultant for Identifiers.

“And I said, ‘Well, why don’t you let me see it? Vargas said. “I concluded that I didn’t stand with the others. I believed the matter was extremely solvable. And I believed I could solve it.”

So, Vargas got the job done. She was able to create a genetic profile from the suspect’s trace DNA. This genetic profile provided valuable information for catching a suspect, such as where their ancestors came from and what race they belonged to.

Once he had a genetic profile, Vargas turned to GEDmatch, an online database where people could upload their DNA results in hopes of finding more relatives after using consumer sites like 23andMe and Ancestry.com. Huh. Users can opt for law enforcement matching, which could allow investigators like Vargas to find matches for their suspects.

Using the results of GEDmatch, Vargas was able to construct the family tree of Roxanne’s killer in 1797.

Vargas said, “Essentially what we’re looking for between these matches is they intertwine. And that led me to a union pair.”

A matching couple is one where two sides of a family tree meet. The couple was born around 1920, and based on that, Vargas could have assumed that they would have children around 1940 or 1950. Thus, the suspect would have to be one of his three sons.

Vargas immediately informed law enforcement of his findings. Investigators conducted a background check on the three sons and removed two of them as suspects. The last had a criminal history and served time for unlawful deviant conduct.

Investigators suspected him, and his name was Patrick Gilham. But before an arrest can be made, they must ensure that Gilham’s DNA matches the DNA left at the crime scene.

Investigators conducted surveys over several days to learn Gilham’s habits and traffic patterns. They even followed him to a laundromat where a secret soldier collected Gilham discarded cigarette butt To be tested for DNA.

The DNA came back as a perfect match for crime scene DNA from the lab, and Gilham was arrested in February 2022. Police interrogated him for more than five hours and insisted that he did not remember Roxanne’s murder. He said that only a demon can do such a thing.

Gilham later pleaded no contest to second-degree murder and was sentenced to at least 23 years in prison.

Gabriella Vargas, who solved this icy case in just four days, hopes this innovative investigative technique can help other families seek justice.

“It’s an honor to be able to work in these cases to bring justice to these victims and to lock down these families,” Vargas said. “And I will never stop. If anything, I am more determined now to solve as many cases as possible.”

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