The Guthrie family reported her missing on Sunday when she failed to turn up for the regular morning church service.
Law enforcement investigated the property after it was made apparent that Nancy had been taken against her will.
In the following days, authorities received an alleged ransom note demanding millions of dollars in bitcoin for her release.
Pima County Sheriff, Chris Nanos, said in a statement: “Just call us. Let her go. Just call us.
“We do not need another bad, tragic ending.”
Nancy was last seen on Saturday evening at her home in Tucson, Arizona, when her daughter, Annie, brought her home from a meal they had together.
Investigators are now working to determine key details, such as what Nancy was wearing at the time of her potential abduction, and whether she was taken away in a vehicle.
Savannah Guthrie breaks her silence
Savannah Guthrie, co-host of NBC’s Today show, reportedly earns upwards of $8 million per year.
In an emotional plea, she has now addressed her mom’s alleged abductor directly.
“We are ready to talk,” she said. “But we need to know without a doubt that she is alive and you have her…Please, reach out to us.
“As a family, we are doing everything we can.
“We want to hear from you, and we are ready to listen.”
Her sister, Annie, added: “Momma, if you’re listening, we need you to come home.”
Police make an arrest
The Department of Justice announced yesterday evening (February 5) that the FBI has made an arrest in connection with the issuing of the ransom note.
Law enforcement have arrested 42-year-old Derrick Callella, in Hawthorne, California.
US attorney, Timothy Courchaine, has reassured the family that they are doing everything they can to safely return Nancy back to her loved ones.
He said: “The Department of Justice will protect victims and families at all costs, and grief profiteers will be held accountable.
“To those imposters who are trying to take advantage and profit from this situation – we will investigate and ensure you are held accountable for your actions.”
The alleged ransom note requested millions in Bitcoin in exchange for Nancy’s return, prompting users online to speculate further that she has been kidnapped for money.
Situation is now a ‘race against time’
Nancy requires critical medication that must be taken every 24 hours to survive, and she disappeared without it.
Sheriff Nanos has since emphasized that her life is ‘in jeopardy.’
Nancy has a pacemaker, which reportedly stopped sending signals around 2:28 a.m. on Sunday.
The 84-year-old woman has been described as roughly being 150 pounds, 5 feet 5 inches tall, in limited health, and cannot walk or run easily.
Hostage negotiator Wallace Zeins has suggested that the case might be more chilling than we thought originally.
Speaking to CNN, the expert noted that it’s possible more than one person was involved in abducting the 84-year-old.
He also noted that the demand for payment with Bitcoin, suggests that the people behind Guthrie’s abduction understand digital currency and may be social media savvy.
The sheriff’s department is also now looking into why a security camera was missing from the front of Guthrie’s house.
Nanos explained: “At 2:12 a.m., software detects a person on a camera, but there’s no video available; they had no subscription and therefore it would rewrite itself.”
Without the subscription service, the potential evidence, which could have shown Nancy’s abductor or provided crucial details about the crime, is gone forever.
In a race against time to find the missing woman, the FBI has offered a $50,000 reward for information leading to Nancy’s whereabouts or the arrest and conviction of anyone involved in her disappearance.