There was no public response to an emotional plea from “Today” show host Savannah Guthrie after her mother’s apparent kidnapping, as authorities hunt for whomever might have forcibly taken Nancy Guthrie from her home in Tucson, Arizona, over the weekend.

The case is urgent because the 84-year-old has a pacemaker and heart issues could die without her medication, Pima County Sheriff Chris Nanos has said. She was last seen Saturday night.

Authorities searched in and around Nancy Guthrie’s home again for several hours on Wednesday. But as of Thursday morning, law enforcement has declined to describe what evidence they found at the scene, or say whether Guthrie’s disappearance was random or targeted.

At least three media organizations reportedly received ransom notes pertaining to Nancy Guthrie’s disappearance — and at least one appears to contain information only the abductor would know, the outlet reported.

Here’s what to know about the case:

Message to kidnappers

In the video shared Wednesday night, Savannah Guthrie’s voice shook as she read a prepared statement, seated between her sister Annie and her brother Camron.

“We are ready to talk. However, we live in a world where voices and images are easily manipulated,” she said, adding. “We need to know without a doubt that she is alive and that you have her. We want to hear from you and we are ready to listen. Please reach out to us.”

Addressing her mother directly, she said the family was praying for her and that people were looking for her.

Law enforcement has not commented on the family’s message.

Ransom notes and a crime scene, but no clear motive

A note emailed Monday to the KOLD-TV newsroom in Tucson included information that only the abductor would know, anchor Mary Coleman told CNN. It also included a dollar amount and a deadline, she said.

“When we saw some of those details, it was clear after a couple of sentences that this might not be a hoax,” she said in an interview aired Wednesday.

According to a person familiar with the investigation, there were signs of forced entry at Guthrie’s home, and several personal items, including Guthrie’s cellphone, wallet and car, were all still there. Authorities are reviewing nearby surveillance video, license plate camera data and cellphone tower records, the person told The Associated Press, speaking on condition of anonymity because they were not authorized to discuss details publicly.

Unspecified DNA samples were collected and submitted for analysis. “We’ve gotten some back, but nothing to indicate any suspects,” the sheriff said.

Investigators returned for the follow-up investigation Wednesday after being at the home earlier in the week for a couple of days, said Kevin Adger, a spokesperson for the Pima County Sheriff’s Department.

She disappeared from a quiet, affluent neighborhood

Nancy Guthrie lived alone in the upscale Catalina Foothills area and was last seen at her home around 9:30 p.m. Saturday. She was reported missing midday Sunday after she didn’t show up to church, leading her family to search her home and then call 911, Nanos said.

A sheriff’s dispatcher said during the search Sunday that Guthrie has high blood pressure, a pacemaker and heart issues, according to audio from broadcastify.com, limiting her mobility.

Her brick home sits in a hilly neighborhood where houses are spaced widely apart and separated from traffic by long driveways, gates and desert vegetation. Saguaro cacti and wispy trees partially block views of the home from the street, and the area appears to have little street lighting at night. That makes it less likely that security cameras captured helpful footage of Guthrie’s disappearance.

Jim Mason, a longtime commander of a search and rescue posse with the Maricopa County Sheriff’s Office, said desert terrain can complicate searches because dense brush and cacti can limit visibility. Mason, whose group is based about 175 miles (280 kilometers) north of Tucson, was not involved in the search for Nancy Guthrie.

A strong mother figure

Savannah Guthrie is in Arizona and hasn’t appeared at the anchor’s desk this week.

The youngest of her three siblings, she grew up in Tucson, graduated from the University of Arizona and previously worked as a reporter and anchor at KVOA-TV before joining “Today” in 2011.

In Wednesday’s video, Savannah Guthrie described her mother as a “kind, faithful, loyal, fiercely loving woman of goodness and light.”

“Talk to her and you’ll see,” she said.

Annie Guthrie, Savannah’s sister, also spoke in the video.

“Mamma, If you’re listening, we need you to come home. We miss you,” she said.