Nancy Guthrie Investigation Stalls at 100 Days as DNA Evidence Remains in FBI Lab

Critical Evidence Awaits Analysis

At the 100-day mark, the investigation into the disappearance of Nancy Guthrie could hang on a strand of DNA that's still being evaluated by scientists at the FBI laboratory in Quantico, Virginia, in hopes of identifying her abductor. Guthrie, the mother of "Today" show co-anchor Savannah Guthrie, was reported missing Feb. 1.

The DNA recovered from Guthrie's home in Tucson, Arizona, was first sent by Pima County sheriff's detectives to a private laboratory in Florida for analysis. Weeks later, the DNA was shipped to the FBI's state-of-the-art crime lab in Quantico, where law enforcement sources tell CBS News the work is ongoing. Earlier in the case, another DNA sample turned out to be a dead end. The sheriff's department recovered DNA from a set of gloves found about 2 miles from Nancy Guthrie's house, but eventually traced them back to a nearby restaurant worker who had no connection to the investigation.

Aside from DNA, the other promising lead that generated a huge amount of attention was video from a Ring doorbell camera, which captured images of a suspect wearing a ski mask, gloves and a backpack at Guthrie's front door the night she vanished. Authorities have said Guthrie likely was targeted before she was taken from her residence. She was last seen while being dropped off at home Jan. 31 by a family member.

Family's Emotional Plea

To honor her mother on Mother's Day, Savannah shared an emotional Instagram post about the 84-year-old and the ongoing search. "Mother, daughter, sister, Nonie -- we miss you with every breath. We will never stop looking for you. We will never be at peace until we find you," she wrote in the post, which included videos and photos of Guthrie and her family.

She continued her plea: "We need help. Someone knows something that can make the difference. Call 1800CALLFBI. You can be anonymous and the reward remains available." The FBI is offering a reward of $50,000 for information leading to the recovery of Nancy Guthrie or the arrest and conviction of anyone involved in her disappearance.

Soon after Nancy Guthrie went missing, several news outlets received ransom notes with specific payment deadlines. The family also received ransom demands. These demands were reviewed by the FBI for authenticity. During an interview, Savannah Guthrie said most of the ransom notes "are not real," but "I tend to believe those are real" regarding the two notes her family received and responded to.

Behind the Scenes Investigation

As a retired FBI supervisory special agent explained: "The public often mistakes silence for inactivity. That is not how major investigations work. The cameras may move on. The investigators usually do not." Behind the scenes, the lead detective and case agents assigned to the Guthrie case have spent the last 100 days doing the slow, frustrating and exhausting work the public never sees like re-interviewing witnesses, sorting through old tips and information with fresh eyes, and running down new tips.

Sheriff Chris Nanos previously said investigators are "closer" to solving the case, though he declined to provide details, citing the integrity of the investigation. The process involves "sorting through tips again with fresh eyes, looking for the one detail that did not fit the first time around. , that digital evidence can take months."

Despite the passage of time, authorities said they have not scaled back efforts entirely and remain hopeful that forensic evidence, surveillance footage or a new tip could provide the break investigators have been seeking for more than three months. While 100 gut-wrenching days for the Guthrie family have passed since Nancy's disappearance, it is far too soon to label this a cold case.

National Attention and Expectations

The case has garnered global attention and a number of vocal critics blaming investigators for a lack of progress in quickly locating Guthrie and her abductor. But for many experts steeped in the intricacies of missing persons cases, the Guthrie investigation also has raised questions about whether the general public has been conditioned to hold outsized and unrealistic expectations of law enforcement's capabilities.

She is believed to be likely dead as she is seemingly without access to life-saving medications, according to the family. Yet investigators continue their methodical work, knowing that one piece of evidence could transform the entire case. The Pima County sheriff said the investigation remains active until either Guthrie is located or all the leads are exhausted.