Federal investigators have released photos of a masked individual, believed to be armed, as the search intensifies for news anchor Savannah Guthrie’s missing mother.

Authorities are trying to identify the person captured in the images, 10 days after 84-year-old Nancy Guthrie vanished from her residence.

Speaking Monday, Savannah Guthrie said her family remains convinced her mother is alive, issuing a renewed plea for public assistance.

Nancy Guthrie disappeared overnight from her Tucson, Arizona home and was last seen on 31 January. Investigators believe she was taken by force.

“As of this morning, law enforcement has uncovered these previously inaccessible new images showing an armed individual appearing to have tampered with the camera at Nancy Guthrie’s front door the morning of her disappearance,” FBI Director Kash Patel said in a statement on X.

He explained that teams had been working to restore surveillance footage from the home that “may have been lost, corrupted, or inaccessible due to a variety of factors – including the removal of recording devices”.

The images represent the first significant development in a case that has drawn national attention for more than a week.

As of Monday, police reported no identified suspects or vehicles linked to the disappearance, the same day Savannah Guthrie released a new video plea urging anyone with information to come forward.

“We believe our mum is still out there,” she said in a video posted to Instagram. “We need your help.”

A second supposed ransom deadline expired Monday evening, following claims that the abductors had demanded $6 million in Bitcoin through media channels. The missed deadline has led many to question whether the kidnapping narrative is accurate.

Former FBI Deputy Director Dan Bongino told Fox that the ransom plot remains one possibility but noted there are other plausible scenarios.“The second possibility would be this was just a crime that went awry. Someone is at the house. Maybe it was a burglary,” he said. “Something went bad, and that you’ve got some bad actors committing another crime, unrelated in other words, requesting a ransom for something you didn’t do just to take advantage of a situation like this.”

The FBI is offering a $50,000 reward for information.