Donald Trump will pursue the death penalty for Nancy Guthrie's kidnappers if they do not release her unharmed.
In a call on Tuesday (Monday US time), the US president said the person or people who took Nancy will face "very, very severe – the most severe" penalties if she is killed.
When asked if the Department of Justice (DOJ) would request the death penalty, Trump responded: "The most, yeah – that's true."
Nancy, 84, is the mother of US TV host Savannah Guthrie.
She was last seen at her Arizona home on January 31 and was reported missing the following day when she didn't show up to church.
On January 4, Trump called Savannah to offer federal support in the search for her mother.
The FBI subsequently revealed haunting images and footage of a masked person standing at Nancy's front door.
The figure appears to be a man wearing gloves, long sleeves, pants, and a balaclava.
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A glove appearing to match the footage from Nancy's home was later found around three kilometres away and has been sent for DNA testing.
Local law enforcement investigating her abduction have confirmed multiple sources have issues demands for ransom.
They did not say if any of the demands are considered credible, nor are they aware of any ongoing communication between the alleged kidnappers and Nancy's family.
The Guthrie family was also ruled out as suspects amid 'cruel' speculation.
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Trump's public commentary on the case has been limited.
His declaration that the DOJ will pursue the death penalty if Nancy's abductors harm her is consistent with other high-profile criminal cases in the US.
Robert Bowers, who is responsible for the Tree of Life Synagogue shooting in 2018, was sentenced to death, as was American mass murderer Dylann Roof.
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