What to know about the disappearance of Nancy Guthrie, mother of 'Today' show's Savannah Guthrie

Authorities are looking for the 84-year-old mother of ''Today'' show host Savannah Guthrie after they say she was taken from her home in Tucson, Arizona, against her will over the weekend.

It's imperative that Nancy Guthrie, who was last seen Saturday night, is found soon because she could die without her medication, Pima County Sheriff Chris Nanos said.

The sheriff held a news conference Tuesday and urged the public to offer tips, but revealed few new details about the investigation. Officials have finished combing through Nancy Guthrie's home and turned it back over to family, Nanos said.

He declined to say whether Guthrie's disappearance was thought to be random or targeted or to describe the evidence found at her home.

There were signs of forced entry at Nancy Guthrie's home, according to a person familiar with the investigation, who was not authorized to publicly discuss details of the case and spoke to The Associated Press on condition of an anonymity. Investigators also found specific evidence in the home showing there was a nighttime kidnapping, the person said.

Here's what to know about the case:

Nancy Guthrie reported missing after she didn't go to church

Initially, searchers used drones and dogs and were supported by volunteers and Border Patrol, Nanos said. But by Monday morning, he said 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.

There were signs of forced entry at the home and several personal items, including Guthrie's cellphone, wallet and car, were all still at the home, the person familiar with the investigation said. Investigators were reviewing surveillance video from nearby homes and information from area license plate cameras and analyzing local cellphone towers data, according to the person. The motive remains a mystery. Investigators do not believe the abduction was part of a robbery, home invasion or kidnapping-for-ransom plot, the person said.

Asked Tuesday whether officials were looking for her alive, Nanos said ''we hope we are.''

DNA samples have been gathered and submitted for analysis as part of the investigation. ''We've gotten some back, but nothing to indicate any suspects,'' the sheriff said.

This week, Savannah Guthrie has been in Arizona and hasn't appeared at the anchor's desk. 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.''

Savannah Guthrie grew up in Tucson, the youngest of three siblings and her father died of a heart attack when she was just 16. She graduated from the University of Arizona and previously worked as a reporter and anchor at KVOA-TV in Tucson. She joined ''Today'' in 2011 and became co-anchor the following year.

Nancy Guthrie held her family together after husband's death

Before the woman's disappearance, viewers got to know Nancy Guthrie through her daughter's show. Savannah Guthrie credited her mom with holding their family together after her father's death.

''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.