Federal investigators are now testing what may be the most promising forensic evidence yet in the disappearance of Nancy Guthrie, the 72-year-old mother of NBC anchor Savannah Guthrie who vanished from her Tucson, Arizona, home earlier this year. A hair sample collected from the residence has been shared with the FBI for advanced analysis, and sources close to the investigation describe the new DNA as "potentially critical" to identifying whoever was inside the house.

The development marks a turning point in a case that has frustrated law enforcement at nearly every forensic juncture. Earlier DNA submissions, including a check through the FBI's Combined DNA Index System (CODIS), failed to produce a match. A glove recovered near the home also came back empty, matching neither known criminals nor other samples taken from inside the residence. Now, investigators are banking on more sophisticated testing to extract usable genetic information from the hair, as the Daily Mail first detailed.

A hair sample and the FBI's next move

The Pima County Sheriff's Department confirmed it has been sharing evidence with the FBI and partner laboratories since the early stages of the investigation. DNA analysis, the department stressed, remains ongoing.

The sheriff's department released a statement outlining the scope of the forensic cooperation:

"The private lab we utilize in Florida continues to share information with the FBI lab & other partner labs across the country. DNA analysis remains ongoing."

That private Florida lab has been working to process what investigators describe as a complex mixed DNA sample recovered from the home. Mixed samples, which contain genetic material from more than one person, are notoriously difficult to separate and interpret. The hair sample, however, could provide a cleaner profile if it contains a root with intact nuclear DNA.

Genetic genealogist CeCe Moore, who Fox News reported has weighed in on the case, offered cautious optimism about the hair evidence. Asked whether contamination could compromise results, Moore said the process is well established but not instant:

"Not after it is cleaned for contamination. They have that process in good shape, but it can take some time."

That timeline matters. Every week without a suspect identification is another week the trail grows colder for a woman whose fate remains unknown.

What CODIS couldn't deliver

The FBI's CODIS database holds millions of DNA profiles from convicted offenders, arrestees, and forensic samples collected at crime scenes nationwide. When investigators submitted DNA from the Guthrie home, the system returned no hits. That result carries two possible readings: either the person who left DNA inside the home has never been profiled in the federal system, or the sample was too degraded or too mixed to generate a searchable profile.

The glove found near the property posed similar problems. It did not match any known criminal profiles, and it did not match other DNA samples collected from inside the house. Investigators have not publicly confirmed whether the glove is connected to the case at all, or whether it was simply debris unrelated to whatever happened to Nancy Guthrie.

Earlier reporting revealed that a blood trail was found at the Arizona residence, raising the stakes of every forensic sample collected from the scene. The presence of blood, combined with the mixed DNA and the hair, paints a picture of a home that holds answers investigators have not yet been able to decode.

An investigation under scrutiny

The Guthrie case has drawn intense public attention, partly because of the family's connection to a prominent national news figure and partly because of questions about how local authorities have handled evidence.

Concerns have surfaced about the pace and coordination of the forensic effort. Questions about whether the Pima County Sheriff's Department moved quickly enough to get evidence into FBI hands have dogged the investigation for weeks. The sheriff's department has pushed back on that narrative, insisting cooperation with federal partners began early and has continued throughout.

Still, the fact that CODIS came back empty and the glove yielded nothing has left some observers wondering whether critical time was lost in the initial evidence collection and processing phase. Advanced DNA testing, including genetic genealogy techniques that can identify suspects through distant family connections, requires high-quality samples. The longer evidence sits before proper preservation and submission, the greater the risk of degradation.

Investigators will need to determine whether the hair sample contains sufficient nuclear DNA for a full profile, or whether mitochondrial DNA testing, which traces maternal lineage but cannot uniquely identify an individual, is the best they can achieve. The distinction could mean the difference between naming a suspect and narrowing the field to a broad family line.

Growing leads, but no suspect named

Authorities have not publicly named a suspect in Nancy Guthrie's disappearance. The investigation has generated what the sheriff's office previously described as a growing number of leads, with Ring camera footage and other surveillance evidence under active review.

Sources have indicated that someone may have visited the Guthrie home before the night she vanished, a detail that could prove significant if the hair sample or other DNA evidence can be linked to a specific individual. Investigators have not confirmed publicly whether they believe the person responsible was known to Guthrie or was a stranger.

A former FBI agent who weighed in on the case has urged investigators to cast a wide net, including scrutiny of individuals connected to the family. No charges have been filed, and no official statements have identified any family member or associate as a suspect.

The absence of a named suspect after months of investigation underscores both the complexity of the forensic evidence and the high bar law enforcement faces in building a case. Mixed DNA, an unmatched glove, and a CODIS dead end have left the hair sample as perhaps the last best hope for a forensic breakthrough.

What comes next

The FBI lab and its partner facilities are now working through the hair sample and continuing to refine analysis of the mixed DNA profile. Authorities have not provided a timeline for when results might be available. Advanced DNA techniques, including genetic genealogy, can take weeks or months depending on sample quality and the size of the reference databases being searched.

Investigators will also need to determine whether any additional physical evidence from the home, or from the surrounding area, warrants re-examination under newer testing protocols. Forensic science has advanced rapidly in recent years, and samples that yielded nothing five or ten years ago can sometimes produce profiles today.

For now, the case remains open, the evidence remains under active analysis, and Nancy Guthrie remains missing.

A 72-year-old woman vanished from her own home, and the answer may come down to a single strand of hair. If the system works the way it should, that ought to be enough.