Guthrie investigators use genetic genealogy to solve cases without initial DNA match

Authorities in Tucson, Arizona, are turning to genetic genealogy to investigate the disappearance of Nancy Guthrie. Advances in this field allow investigators to explore DNA evidence previously unsolvable, offering new avenues for solving cold cases like hers.

In a significant departure from traditional investigative techniques, authorities investigating the disappearance of Nancy Guthrie in Tucson, Arizona, are turning to the emerging field of genetic genealogy. A few years ago, the discovery of a glove near her residence with no match in any DNA database would have been an insurmountable obstacle. However, advancements in genetic genealogy have provided law enforcement with new avenues to pursue leads that were previously inaccessible.

Exploring New Genetic Leads in the Case

Authorities in Pima County, Arizona, have revealed they are now exploring the potential of genetic genealogy to further investigate DNA evidence related to the case. A pair of gloves found approximately two miles from Guthrie's home have raised questions, especially after being linked to a troubling video captured by a camera at Guthrie's front door. The footage shows a person wearing gloves that appear to be similar to those found at the scene. Genetic genealogy could help clarify these pieces of evidence and open new paths for investigation.

Moreover, DNA found on Guthrie's property, which does not match hers or anyone in her immediate circle, has failed to yield any leads through the FBI's national DNA database, CODIS (Combined DNA Index System), according to Pima County Sheriff Chris Nanos. Despite this, experts in genetic genealogy are optimistic that the technology may still yield new leads.

Understanding Genetic Genealogy

Genetic genealogy involves comparing DNA samples from crime scenes with publicly accessible genetic databases, which contain millions of genetic profiles. By identifying distant relatives through these databases, investigators can construct family trees that may point toward potential suspects. This technique has played a critical role in solving high-profile cases, including the arrest of Bryan Kohberger, who confessed to the 2022 murders of four University of Idaho students. Kohberger’s arrest was made possible, in part, by genetic genealogy, though it wasn’t the primary factor in his apprehension.

CeCe Moore, a genetic genealogy expert, shared with CNN that even a small genetic match could provide crucial leads in solving cases. "We get a list of people who share DNA with that unknown person. It can be as little as 1%, or even less," Moore explained.

Challenges in Utilizing Genetic Genealogy

Despite its promise, genetic genealogy is not without its challenges. The timeline for results can vary significantly—some cases can yield results within minutes, while others may take years to solve. Moore pointed out that some cases she’s worked on have taken over seven years to reach a breakthrough. While the method has led to significant successes, such as the identification of the Golden State Killer, it does not automatically solve crimes. Investigators must still carefully piece together all available evidence, and often, genetic genealogy only helps narrow down the suspect pool. This was evident in the Golden State Killer case, where DNA from the crime scene was matched to a suspect through DNA collected from discarded tissues.

Notable Successes and Legal Considerations

One of the most notable successes of genetic genealogy occurred in 2018 when investigators used DNA from a crime scene to identify the Golden State Killer, Joseph DeAngelo. This breakthrough was made possible through GEDmatch, a public database where individuals upload their DNA for genealogical purposes. Within four months, investigators were able to find potential relatives of the killer, ultimately narrowing the suspect pool to three individuals. One of them, Joseph DeAngelo, a former police officer, was identified as the perpetrator after investigators matched DNA from his trash to the crime scene. DeAngelo, arrested at the age of 72, was convicted in 2020 and is now serving a life sentence.

Since then, genetic genealogy has been employed in several high-profile investigations, not only to identify suspects but also to solve cases involving unidentified victims. For instance, a 1921 victim of the Tulsa Race Massacre was identified through genetic genealogy, revealing that the person was a World War I veteran.

Privacy Concerns and Limitations

While genetic genealogy shows immense promise, it raises serious privacy concerns. The debate revolves around the use of personal genetic data for law enforcement purposes. Commercial DNA testing companies like 23andMe, AncestryDNA, and MyHeritage, primarily designed for personal heritage research, usually restrict law enforcement access to their databases unless compelled by a court order or warrant. For instance, 23andMe has reported receiving only 11 law enforcement requests in the past decade, none of which resulted in the release of data without consent.

CeCe Moore acknowledged that there are only two major databases, GEDmatch and FamilyTreeDNA, that allow law enforcement access to their data. However, these databases are much smaller in comparison to the commercial databases, with fewer than two million profiles available. Moore also noted that these open-source databases are mostly comprised of individuals of Western European descent, which could limit the ability to find genetic matches for individuals from other ethnic backgrounds.

The Future of Genetic Genealogy in Law Enforcement

Despite these challenges, genetic genealogy is evolving, and its potential for solving cold cases continues to grow. Moore highlighted that the success of these investigations often depends on people’s willingness to share their genetic data for genealogical purposes. She noted that the records available are predominantly from individuals with Western European ancestry, which may pose difficulties for people from other ethnic groups.

For Nancy Guthrie's family, there remains hope that genetic genealogy may eventually provide answers, though it’s unclear how long it will take. Moore suggested that in some cases, law enforcement may be forced to seek court orders to access large commercial genealogy databases, potentially leading to legal battles. As this technology gains wider acceptance, it remains to be seen how privacy concerns will be addressed and whether more individuals will consent to have their genetic profiles used in criminal investigations.

The investigation into Nancy Guthrie’s disappearance is ongoing, and while genetic genealogy holds promise, it is still a work in progress. The future of law enforcement's use of genetic genealogy will depend on balancing the benefits of solving crimes with the need to safeguard individual privacy.

Sources:

• CNN
• ABC News
• NBC News
• With no initial DNA match, Guthrie investigators turn to one of their newest tools to crack cases: genetic genealogy