Could Genetic Genealogy Crack the Case of Nancy Guthrie? Inside the Technology Investigators May Use

The 84-year-old disappearance of Nancy Guthrie from her house in Tucson has reached a critical phase, and investigators are intensifying their research, leveraging advanced forensic devices to identify a suspect.

Genetic genealogy has been among the most closely watched techniques, an approach that has been rapidly developed over the years and has aided in solving intricate criminal cases over the last few years.

Police have reported that DNA evidence taken during the inquiry, such as samples that were discovered on items surrounding Guthrie's property have yet to match any known offenders in the national criminal databases. This has led authorities to review how the analysis of genealogical DNA can potentially be a breakthrough.

DNA Evidence Offers Leads But No Match Yet

Investigators have confirmed that the DNA retained through the probe is not yet a match with any known offenders in federal databases. Specifically, the CODIS, which has millions of profiles of offenders, did not find any matches with the DNA of a glove found near the crime scene.

An unfamiliar trail is not an indication of the loss of the trail. Rather, it singles out a major drawback of the traditional DNA databases: they merely store profiles of persons who were already arrested or convicted of some offence. In the case of a suspect who is never entered into the system, the investigators will depend on other ways of identifying the suspect.

This is where genetic genealogy comes into play.

What Is Genetic Genealogy?

Genetic genealogy is a crime-solving method that incorporates DNA testing with studies on family trees. Instead of merely looking to find a perfect match, at a crime scene, a DNA profile is compared by investigators to genetic data of public or consumer genealogy databases to find possible relatives of an unknown suspect.

According to experts, even remote family members can give crucial clues. The mapping of the family linkage and narrowing down the potential suspects will help the team to locate suspects that the investigators would not have known otherwise.

As per case reports, police are now considering this technique in the ongoing investigation.

One of the experts informed ABC News that, in the case of failure by other investigative leads, the other knows that the technique of investigative genetic genealogy will unearth the actual perpetrator, confirming the increasing confidence among forensic professionals in the technique.

A Tool That Has Solved Major Cases

Genetic genealogy has already taken a pivotal role in some high-profile criminal investigations. An example is in the University of Idaho murders case, where the investigative group applied genealogical DNA methods to the crime scene evidence in order to identify a match between the evidence and the family of a suspect, Bryan Kohberger, before subsequently establishing the match by the conventional DNA test.

This is done by determining those who have shared portions of DNA with the suspect. From there, genealogists create a family tree and narrow down the candidates based on age or location, among other factors, until investigators find a likely suspect.

There have been occasions where arrests have been made after a few days or weeks, since ample DNA evidence has been found.

Challenges and Controversies Around the Technology

Genetic genealogy, however, does not lack controversy, despite being successful. Given its required access to consumer DNA databases, primarily built to research ancestry and not criminal investigations, the technology raises privacy concerns among advocates.

Also, the process is time-consuming. According to the experts, it could require weeks or even months to construct proper genealogical ties and validate the leads using regular forensic testing, depending on the nature of the available DNA evidence.

Nevertheless, the investigators indicate that they are chasing all lead possibilities as they seek to know what befell Guthrie and who did it.

Over three weeks since Guthrie disappeared, authorities are still examining evidence and soliciting the help of people.

Although the case is still unresolved and undergoing progression, such improvements in forensic science, especially in genetic genealogy, could still offer the breakthrough investigators need.