Signs of forced entry found at Arizona home of Today show host Savannah Guthrie's mother Nancy

Signs of forced entry have been found at the Arizona home of Today show host Savannah Guthrie's mother, Nancy Guthrie, a person close to the investigation confirmed on Tuesday.

The update came hours after Savannah shared a post online, asking for prayers to help bring back her 84-year-old mum, who is believed to have been taken against her will.

The host described her mother as "a woman of deep conviction, a good and faithful servant" in a social media post late Monday.

She asked supporters to "raise your prayers with us and believe with us that she will be lifted by them in this very moment. Bring her home."

Nancy must be found soon because she could die without her medication, Pima County Sheriff Chris Nanos said, urging whoever has her to free her.

"If she’s alive right now, her meds are vital. I can’t stress that enough. It’s been better than 24 hours, and the family tells us if she doesn’t have those meds, it can become fatal," Nanos said.

Investigators also found specific evidence in the home showing there was a night-time kidnapping, the person told The Associated Press.

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Several of Nancy’s personal items, including her mobile phone, wallet and her car, were still there after she disappeared.

Investigators are reviewing security camera footage from nearby homes and working to analyse data from mobile phone towers. Police are also reviewing information from license plate cameras in the area, according to the person, who was not authorised to publicly discuss details of the case and spoke to AP on condition of anonymity.

The motive remains a mystery. Investigators do not believe at this point that the abduction was part of a robbery, home invasion or kidnapping-for-ransom plot, the person said.

The sheriff and the local FBI chief held a press conference and urged the public to offer tips, but they revealed few new details about the investigation.

Nanos declined to say whether Nancy’s disappearance was thought to be random or targeted or to describe the evidence found at her home.

For a second day, Today opened on Tuesday with Nancy's disappearance, and Savannah was again missing from the desk as co-host, as she is currently in Arizona.

Nancy was last seen Saturday night at her home in the Tucson area, where she lived alone and was reported missing Sunday.

Someone at her church called a family member to say she was not there, leading family to search her home and then call police, Nanos said.

Nancy has limited mobility, and officials do not believe she left on her own. Nanos said she is of sound mind.

In the hours after she disappeared, searchers used drones and dogs and were supported by volunteers and Border Patrol. The homicide team was also involved, Nanos said.

On Monday morning, search crews were pulled back.

"We don’t see this as a search mission so much as it is a crime scene," the sheriff said.

Savannah is the youngest of three siblings and credits her mum with holding their family together after her father died of a heart attack at age 49, when she was just 16.

"When my dad died, our family just hung onto each other for dear life because it was such a shock. We were just trying to figure out how to become a family of four when we’d always been a family of five," she said on Today in 2017.

The journalist often brought her mum on Today as a guest too.

"She has met unthinkable challenges in her life with grit, without self-pity, with determination and always, always with unshakeable faith," Savannah said on the show in 2022 on Nancy's 80th birthday.

"She loves us, her family, fiercely, and her selflessness and sacrifice for us, her steadfastness and her unmovable confidence is the reason any of us grew up to do anything."

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