NEWSInvestigators Involved in Nancy Guthrie Case Resort to Same Genetic Testing Method Used to Catch Bryan Kohberger
Officials announced they are using a new approach to track down Nancy Guthrie's kidnapper.
Feb. 18 2026, Updated 1:24 p.m. ET
Investigators searching for Savannah Guthrie's missing mom are now turning to the same forensic strategy that caught Bryan Kohberger in the 2022 University of Idaho murders.
The Pima County Sheriff's Department confirmed in a press release on Tuesday, February 17, that a pair of gloves found near Nancy Guthrie's Tucson, Ariz., home did not "trigger a match" in CODIS, the FBI's national database.
"Investigators are currently looking into additional investigative genetic genealogy options for DNA evidence to check for matches,” the department said.
How Does IGG Work?
DNA found on a knife sheath left at the crime was identified as Bryan Kohberger's using IGG.
The technique, known as IGG, involves uploading DNA found at the crime scene to genealogy databases like Ancestry.com, GEDmatch or 23andMe.
If a relative of the person whose DNA was collected from the scene submitted their own sample into the system, investigators can build a family tree that helps them narrow in on a suspect.
The method has in recent years become a useful tool for identifying suspects, including in the case of Kohberger, whose DNA was discovered on the knife sheath he left behind on one of the victim's bed.
IGG Also Caught the Golden State Killer
The Golden State Killer was identified in 2018 with the help of investigative genetic genealogy.
Kohberger is currently serving life in prison after pleading guilty to avoid the death penalty in July 2025.
The groundbreaking technique first garnered attention in 2018 after law enforcement used it to track down the Golden State Killer, a prolific serial rapist and killer in California during the 1970s and '80s.
Joseph DeAngelo, former police officer and family man, flew under the radar for decades.
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How Long Has Nancy Guthrie Been Missing?
Nancy Guthrie was taken from her home in the early morning hours of February 1.
84-year-old Nancy mysteriously vanished from her Tucson, Ariz., on Sunday, February 1.
The retiree's daughter Annie and son-in-law Tommaso Cioni, were reportedly the last to see her alive at their nearby home the night before.
Authorities quickly determined based on evidence at the scene, including blood splatter outside the upscale Catalina Foothills residence, that the Today star's mother had been kidnapped.
A Suspect Was Captured on Nancy Guthrie's Doorbell Camera
Footage of masked suspect tinkering with Nancy Guthrie's doorbell camera was released by the FBI last week.
Last week, the FBI released terrifying doorbell camera footage of a masked suspect on the night she went missing.
It was revealed early on that the Google Nest camera attached to the door was disconnected just before 2 a.m., and the camera’s software detected movement minutes later.
While initially there was no video available because Nancy didn’t have an active subscription to the company, they were able to pull footage from "residual data located in backend systems."
