Nancy Guthrie Update Today: Expert Says Digital 'Blackout' May Reveal Kidnap Suspect

The person who allegedly abducted Nancy Guthrie may have left behind a critical clue by trying to erase their digital footprint, according to one of America's leading forensics experts.

Heather Barnhart, a digital forensics specialist with Cellebrite and the SANS Institute, said cell tower data, Wi-Fi logs and other digital traces could prove decisive in a case where physical evidence has so far stalled.

'The loudest evidence can be the lack of evidence,' she told Fox News Digital on 26 February.

Barnhart is not speculating from a distance. She analysed the phone and computer of Bryan Kohberger, the former criminology PhD student now serving life for the murders of four University of Idaho students in 2022. It was his phone's silence that helped convict him.

How Kohberger's Phone Gave Him Away

Kohberger disabled his mobile signal, switched off Wi-Fi and powered down his handset before the killings. He switched it back on roughly 40 minutes later. That deliberate gap — on a fully charged device, in the middle of the night — gave investigators what Barnhart described as a 'tunnel to look down.'

'Kohberger literally created bookends around the crime by turning off his device,' she said. 'Right before the murder, his phone was turned off, and then within like 40 minutes or so after it was turned back on.'

Phone records showed the shutdown was user-initiated, not due to a dead battery or a dropped signal. That distinction mattered in court.

Even aeroplane mode was not the shield Kohberger may have assumed. Barnhart recalled that her own device, set to aeroplane mode during the investigation, still registered a location change when she crossed time zones. That experience directly informed her analysis of Kohberger's digital trail.

What This Means for the Guthrie Case

Nancy Guthrie, 84, the mother of NBC Today show co-host Savannah Guthrie, is believed to have been taken from her Catalina Foothills home against her will around 2.30am on 1 February. The Pima County Sheriff's Department has said she did not leave voluntarily.

Surveillance footage released by the FBI on 10 February shows a masked, armed individual wearing gloves and a backpack at her front door, apparently trying to disable her Nest doorbell camera.

The suspect wore long sleeves and appears to have avoided shedding traceable genetic material. DNA samples collected from the property yielded no match in the FBI database, the sheriff confirmed.

With physical forensics at a reported dead end, digital evidence may carry the weight.

Barnhart said investigators would be examining cell tower records for anomalies around the time of the alleged abduction. In a quiet residential area at 2.30am, most phones sit still on bedside tables, pinging the same nearby tower. A device that suddenly goes dark — or one that had previously pinged local towers while its owner allegedly scouted the area — stands out.

'If the person prepped, they wouldn't ping that tower, but if they went ahead of time and scoped it out or planned, they would have,' she said. 'And then you can also look for entry and exit. Eventually you're going to turn your phone back on.'

The Digital Traces That Are Hardest to Hide

Beyond cell towers, Barnhart pointed to several other avenues that could place a suspect at the scene.

A phone that briefly 'touches' a home Wi-Fi network — without actually connecting — can still register its presence. Traffic cameras across Pima County may have captured a vehicle or a face. Router logs from neighbouring properties could show unfamiliar devices in range.

Neighbours have told investigators about a suspicious individual seen in the Catalina Foothills around 11 January, three weeks before Guthrie vanished, Men's Journal reported. The FBI has also recovered doorbell camera images it believes may show the suspect visiting the home on a separate day prior to the alleged abduction, though without a Nest subscription, timestamps could not be confirmed.

In the US, investigators typically obtain court orders to pull historical location data from mobile carriers. Combined with smart doorbells, city-run cameras and router logs, that data can reconstruct minute-by-minute movements.

'We hope in Nancy Guthrie, that whoever has her made a mistake,' Barnhart said, 'and that we can uncover that footprint.

Where the Investigation Stands

The FBI relocated its command post from Tucson to Phoenix on 27 February but insisted the investigation remained at full speed.

More than 23,000 tips have been received. Savannah Guthrie's family has offered a reward of up to $1m (£740,000) for information leading to her mother's recovery.

Anyone with information is urged to contact the FBI tip line at 1-800-CALL-FBI.