Nancy and Savannah Guthrie
Nancy Guthrie has been missing for more than 50 days. Screenshot/Facebook

More than fifty days after Nancy Guthrie vanished from her Arizona home in the middle of the night, the search for the missing mother of television host Savannah Guthrie has entered a dramatic new phase. Helicopters have been spotted flying low across the desert as investigators deploy advanced technology in a desperate attempt to find the 84 year old.

Despite the intense search, authorities have not confirmed that Nancy is dead. Instead, officials say they are exhausting every possible lead as the case grows increasingly urgent.

Savannah Guthrie Shares Emotional Plea

The painful mystery surrounding Nancy Guthrie has deeply affected her family. Savannah Guthrie recently spoke publicly for the first time since her mother disappeared, sharing an emotional message during an interview with Hoda Kotb.

Savannah described the emotional toll of the past several weeks while pleading for anyone with information to come forward.

She said, 'Someone needs to do the right thing. We are in agony. It is unbearable.'

The Today show co host admitted she wakes up in the middle of the night thinking about what her mother may have experienced.

'I wake up every night in the darkness and imagine her terror,' Savannah said. 'Those thoughts demand to be thought. But she needs to come home now.'

Friends and colleagues have described Savannah as showing both deep pain and strong determination as she continues to speak out in hopes of finding answers.

Helicopters Search Desert

Authorities have now turned to technology in an effort to locate Nancy. Helicopters belonging to the Pima County Sheriff's Department have been flying slow grid patterns over the Tucson desert.

The aircraft are equipped with specialised devices that investigators refer to as signal sniffers. These devices attempt to detect the Bluetooth signal from Nancy's pacemaker.

Observers reported seeing one helicopter flying unusually low near her home while the equipment was visible on the landing skid.

Investigators hope the signal might help them locate Nancy if she is nearby. However experts warn the technology has serious limitations.

Digital evidence analyst Karl Epps explained that pacemakers use near field communication which works only at very short distances.

He said, 'It is very unlikely we will get a signal unless we are right on top of it.'

Epps compared the system to wireless earphones that disconnect when a person walks only a short distance away.

Key Clues From the Night Nancy Disappeared

Investigators believe several events from the night Nancy disappeared may hold critical clues.

Records show that her pacemaker disconnected from her mobile phone at 2:28am on 1 February. Around the same time, the Nest security camera outside her home also stopped transmitting.

Earlier that evening Nancy had been dropped off at her house by her son-in-law at approximately 9:50pm.

When she failed to appear at church the following morning, relatives went to check on her at around 11:00am and discovered she was missing. Her phone and personal belongings were still inside the house.

Security footage captured a masked person standing outside Nancy's front door that night. The FBI described the figure as a man around five feet nine to five feet ten tall, wearing black clothing and carrying an Ozark Trail backpack.

Investigators also discovered DNA evidence at the home that does not match Nancy or anyone known to her.

18,000 Tips Received from the Public

The case has generated enormous public attention. Authorities say they have received nearly eighteen thousand tips from the public, including thousands in a single day.

Residents in the community have placed flowers, candles and handwritten notes outside Nancy's home as the search continues.

For now, investigators insist that Nancy Guthrie has not been declared dead. The search remains active as authorities pursue every possible clue in the hope of bringing her home.