One hundred days after 84-year-old Nancy Guthrie was taken from her Tucson home, the single strand of DNA evidence recovered from the scene remains under analysis at the FBI's crime lab, and investigators still have no public suspect, no arrest, and no confirmed leads.

The case, which has drawn national attention partly because Guthrie is the mother of "Today" show host Savannah Guthrie, now hinges in large part on whether federal forensic work can identify whoever left biological evidence inside the Arizona residence. Law enforcement sources told CBS News that testing was still underway as the investigation crossed the 100-day threshold on Monday, the New York Post reported.

That timeline, more than three months of lab work with no public result, raises hard questions about the pace of justice for an elderly woman who vanished in the early hours of February 1.

What investigators know so far

Security footage from Nancy Guthrie's doorbell camera captured a masked man loitering around her doorstep on the night police believe she was kidnapped. Blood spatters were later discovered on her front doorstep. Inside the home, investigators recovered a DNA sample that Pima County sheriff's detectives initially sent to a private lab in Florida.

Several weeks after Guthrie went missing, the evidence was turned over to federal investigators. The FBI had offered early on to analyze the DNA at its own facility.

The delay between local and federal handling of the evidence has been a source of friction. As we previously reported, Pima County's sheriff faced scrutiny for blocking FBI access to key evidence in the early stages of the investigation, a decision that critics say cost precious time.

Pima County Sheriff Chris Nanos declined to discuss the DNA sample or its status. He framed his silence as a matter of investigative integrity.

"It would be highly inappropriate of me to speak to the evidence. We have to keep the integrity of this case. If we make an arrest, that individual has the right to a fair trial. I can't sit here and address all of that."

Nanos added a broader pledge: "We are working hard with all of our partners to resolve this case, and we will."

Why the DNA work takes so long

Retired FBI special agent Jason Pack explained that the forensic process bears little resemblance to what the public sees on television. DNA analysis can involve building out entire family trees to identify suspects, painstaking genealogical work that demands accuracy over speed.

"That kind of work is slow because it has to be right."

Pack said the process "takes far longer than television crime dramas would have people believe." For a family waiting 100 days with no answers, that distinction between fiction and reality offers cold comfort.

Lance Leising, an ex-FBI special agent who previously worked in Arizona, offered additional context on how the bureau would prioritize the evidence. Not all DNA recovered from a home carries the same weight.

"An item containing DNA, such as a strand of hair found somewhere in a house, is one thing, but a strand of hair near the victim's last known location, such as in her bed, would be a high priority for the FBI."

The implication is clear: location within the home matters. A sample found near where Guthrie slept or was last seen would carry far more investigative significance than one recovered from, say, a hallway or kitchen counter. Investigators have not disclosed where in the home the DNA was found.

A family in limbo

For Savannah Guthrie, the disappearance has turned deeply personal in public view. The "Today" anchor's Easter message earlier this year laid bare the weight of her mother's absence, a reminder that behind the headlines sits a family enduring an agonizing wait.

Nancy Guthrie, 84, lived alone in her Tucson home. The masked figure caught on her doorbell camera, the blood on the doorstep, and the absence of any ransom demand or public communication paint a grim picture, though investigators have not publicly characterized the case beyond treating it as a kidnapping.

No credible leads or suspects have been publicly identified. The sheriff's office has not disclosed what lines of inquiry were pursued and ruled out over the past 100 days.

Meanwhile, Sheriff Nanos has said investigators are closer to solving the case, though he offered no specifics to support that claim. The gap between that assertion and the visible lack of progress, no arrest, no named suspect, no public timeline for DNA results, is difficult to square.

Lingering questions about the investigation

The Nancy Guthrie case has exposed fault lines in how local and federal law enforcement coordinate on high-profile investigations. The initial decision to send the DNA sample to a private Florida lab rather than the FBI's own facility cost weeks. Whether that delay materially harmed the investigation remains an open question, one that Nanos has refused to address.

A retired Arizona lawman has publicly raised the possibility that Guthrie may have been taken across the border into Mexico, and has alleged that local officials worked to keep the FBI out of the investigation in its critical early days. Separately, a private investigator has pointed to a possible cartel link in the disappearance, a theory that, if credible, would underscore the dangers that border-state residents face and the urgency of federal involvement from the start.

None of these theories have been confirmed by law enforcement. But the sheer range of speculation, combined with the absence of official information, speaks to a vacuum that authorities have done little to fill.

Tucson sits roughly 60 miles from the Mexican border. The proximity alone does not prove any particular theory. But it does mean that every day without answers is a day the trail grows colder, and the range of possibilities grows harder to narrow.

What comes next

The FBI lab's findings, whenever they arrive, could break the case open or leave investigators where they started. If the DNA belongs to someone already in a criminal database, a match could come relatively quickly. If it requires genealogical tree-building, the kind of work Pack described, the wait could stretch considerably longer.

Sheriff Nanos has promised resolution. The FBI has committed resources. But 100 days in, the public record shows an 84-year-old woman taken from her home in the dark, a masked figure on camera, blood on the doorstep, and a single piece of biological evidence sitting in a federal lab.

That is not nothing. But for a family and a community waiting for answers, it is not nearly enough.

When an elderly woman can be snatched from her own home in an American city and the best law enforcement in the world needs more than 100 days just to process the evidence, something in the system is not working the way it should.