Investigators working on the Nancy Guthrie case have turned to genetic genealogy, a modern DNA technique that has helped solve major criminal investigations when traditional databases failed.
Authorities in Arizona, USA, confirmed this week that they are now testing DNA evidence using investigative genetic genealogy after initial checks found no match in standard law enforcement systems.
The move comes as police continue searching for answers over Guthrie’s disappearance, which has drawn international attention due to her links to American broadcaster Savannah Guthrie.
The new DNA testing could prove vital in identifying suspects if the people involved have never been arrested or added to criminal databases.
What happened in the Nancy Guthrie case, and why does it matter?
The Nancy Guthrie case centres on the disappearance of Nancy Guthrie, an elderly woman who vanished from her home in Tucson, Arizona, earlier this month.
Police reportedly recovered a glove found around two miles from her home, along with other DNA samples located inside the property. However, investigators failed to find any match through the main national DNA database used by law enforcement.
DNA from the gloves found did not come back with a match in CODIS.
No DNA submitted to CODIS involving the Nancy Guthrie investigation has come back with a match, according to the sheriff.— Brian Entin (@BrianEntin) February 17, 2026
That failure pushed authorities towards genetic genealogy, which can identify people through relatives rather than direct DNA matches.
The case matters because it highlights how modern forensic science is changing investigations, and how law enforcement now relies on DNA tools once reserved mainly for cold cases.
What is investigative genetic genealogy in simple terms?
Investigative genetic genealogy (often shortened to IGG) is a method that uses DNA evidence to trace a suspect through family connections.
Instead of looking for an exact match in a police DNA database, investigators search for genetic similarities in wider genealogy data, then build a family tree to narrow down potential suspects.
As suspected – they will use investigative genetic genealogy in Nancy Guthrie investigation.
This is what helped catch Kohberger. https://t.co/TOvYIba4xC— Brian Entin (@BrianEntin) February 17, 2026
If police can’t identify a person directly, they try to identify their relatives instead.
This can help investigators find leads when the suspect has never been arrested and does not appear in criminal DNA records.
Why did the DNA not match in traditional law enforcement databases?
The main reason investigators hit a wall is that traditional databases only contain DNA from people already known to police.
That usually means:
- convicted criminals
- people previously arrested
- people who voluntarily gave DNA in specific legal circumstances
If the suspect has never been caught before, their DNA simply will not exist in the system.
BREAKING🚨: High-Tech DNA Dragnet Intensifies as Investigators Turn to Genetic Genealogy, Rapid DNA, and Private Labs in Race to Crack Nancy Guthrie Case.
Authorities are escalating their forensic strategy in the search for answers in the Nancy Guthrie investigation, deploying… pic.twitter.com/pc75OXICow
— Prince Panwar (@panwap) February 17, 2026
That appears to be the problem in the Nancy Guthrie case, where DNA collected from evidence reportedly returned no match in standard checks.
How can genetic genealogy help solve the Nancy Guthrie case?
Genetic genealogy could help investigators by:
- identifying distant cousins or relatives linked to the DNA sample
- allowing detectives to build a family tree
- narrowing down possible individuals by age, location, and history
- giving the police a shortlist of people to investigate further
If DNA from the glove or the house belongs to a kidnapper or intruder, the method could point authorities towards the family line of the person responsible.
Even a partial match can be enough to create a breakthrough.
Which famous cases has genetic genealogy solved before?
Genetic genealogy has already made headlines in recent years after helping identify suspects in serious crimes.
The Golden State Killer case
One of the most well-known successes came when investigators used genealogy DNA to track down a suspect linked to decades of rape and murder cases in California.
Authorities reportedly used distant family links, built an extensive family tree, and narrowed the search down until they identified the correct individual.
That arrest became a major moment for forensic science and proved the technique could work.
The Idaho student murders
Another high-profile case involved the killings of four university students in Idaho in 2022. Investigators used DNA evidence from the scene and worked through genealogy-style analysis after traditional database searches failed.
The method helped investigators identify a suspect and eventually arrest him.
Bear Brook murders
Genetic genealogy also helped identify victims of a decades-old murder case involving human remains discovered in barrels. It provided answers for families who had waited years for identities and closure.
These cases show why investigators believe the technique could also help in the Nancy Guthrie case.
Is genetic genealogy controversial?
Yes, and it remains one of the most debated forensic tools in modern policing.
Privacy campaigners often argue that genetic genealogy risks pulling innocent relatives into investigations.
Supporters argue the opposite: that it helps solve the most serious crimes, including murder and abduction, and can bring justice to victims.
The controversy becomes stronger when DNA databases include information submitted by the public for ancestry purposes, not criminal investigations.
Could the UK police use genetic genealogy in similar cases?
The UK already has one of the largest law enforcement DNA systems in Europe, but genetic genealogy presents different legal challenges.
British policing must consider strict privacy standards, including data protection laws and human rights safeguards.
If UK forces wanted to use the same approach widely, it would likely require:
- clearer legal permission
- stronger public consent rules
- independent oversight
- limits on when the method can be used
UK investigators tend to focus on traditional DNA databases first, but growing international success could increase pressure for wider use of genealogy-based techniques.
What happens next in the Nancy Guthrie case?
Investigators are now expected to:
- process DNA through genetic genealogy testing
- compare results to broader genetic matches
- identify possible relatives
- develop a shortlist of suspects
- follow up through surveillance, interviews, and further evidence
If successful, the technique could lead police to a suspect who would otherwise remain completely unknown.
However, the process can take time, and results may depend on whether usable DNA exists and whether any relatives appear in accessible genetic records.
