The FBI has released images of a masked person in the hunt for news anchor Savannah Guthrie's mother.

Officials are seeking to identify the individual, who they say was armed, more than eight days after 84-year-old Nancy Guthrie disappeared from her home.

Savannah Guthrie said on Tuesday her family believes their mother is still alive and issued a new appeal to anyone with information.

Nancy Guthrie disappeared in the middle of night from her Tucson, Arizona, home and was last seen on 31 January. Authorities believe she was taken against her will.

"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 said authorities had been working to recover images from the home surveillance system that "may have been lost, corrupted, or inaccessible due to a variety of factors - including the removal of recording devices".

Officials also released two short videos showing the person approach the front door of Nancy Guthrie's home, then check the camera before moving away, picking up some vegetation from the ground and using it to cover the camera lens.

Savannah Guthrie shared the new video on Instagram. "Someone out there recognises this person," she said on Tuesday. "We believe she is still out there. Bring her home."

It marks the first major breakthrough in a case that has gripped the country.

On Monday, police were still saying they had yet to identify any suspects or vehicles connected to Nancy Guthrie's disappearance, the same day that Savannah Guthrie issued a new video appeal to anyone with information.

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

It was the fourth video appeal released by the family in recent days, including one indicating they would be willing to pay for their mother's safe return.

Police have said Nancy Guthrie needs daily medication and has limited mobility.

The FBI is offering a $50,000 (£36,000) reward for information in the case.

White House press secretary Karoline Leavitt said President Donald Trump has reviewed the footage. She said he encouraged people with any information to contact authorities.

"The prayers of this entire White House are with Savannah and her family at this time," she said. "We hope this person is found soon and her mother is brought home safely."

Last week, Pima County officials said the home's doorbell camera was disconnected at 01:47 local time and the camera's software had registered motion a short time after, at 02:12.

At 02:28, the app on her pacemaker, an implanted cardiac device, disconnected from her phone.

Police also said they had found blood on Nancy Guthrie's porch and analyses confirmed it was hers.

Authorities have said there were taking seriously an email with a ransom note, sent to US media outlets and stating a Monday deadline, the BBC's US partner CBS reported.

A previous apparent deadline for ransom, which was demanded in Bitcoin, passed on 5 February.

It was one of three reported ransom notes sent in the case. Officials made one arrest last week in relation to a hoax ransom note.

The doorbell camera at Guthrie's home has been identified in images as a Nest product, which is part of Google Home's range of devices.

While law enforcement officials initially said that video of the incident was not available because Guthrie lacked a subscription for recorded video access, it appears that Google was able to pull footage from the doorbell around the time of her disappearance.

Even without a paid subscription to Google Home, most owners of a Nest camera or doorbell have access to a live-stream of video, as well as up to three hours of imagery or footage of any incident captured by their device.

A subscription allows a user to access weeks of recorded video from their doorbell camera.

Given these functionalities, a Nest doorbell camera is essentially equipped to record constantly.

In its privacy policy, and in a guide to security of its Nest products, Google says that video footage is sent to the company from all devices that have the camera turned on.

Google did not respond to emails seeking comment on whether it had provided the footage in response to a warrant from investigators.

It is unclear why this footage was not released sooner. (BBC)

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