WASHINGTON — In the ongoing search for Nancy Guthrie, the 84-year-old mother of “TODAY” show host Savannah Guthrie, law enforcement officials are increasingly convinced that criminal activity is involved.

According to Pima County Sheriff Chris Nanos, Guthrie was last observed by some of her children at her Arizona residence on Saturday night.

The alarm was raised when deputies were summoned to Guthrie’s home in Catalina Foothills around noon on Sunday, following reports from her family that she missed a church service and was nowhere to be found at her house.

Despite the efforts of search-and-rescue teams, K-9 units, and deputies, who scoured the area throughout the day and night, Guthrie remains missing.

Sheriff Nanos noted that as the investigation unfolded, certain elements of the situation suggested that foul play might be a factor.

“We saw some things at the home that were concerning to us,” he said at a Monday news conference. “We do in fact have a crime. We are asking for the community’s help.” 

Nanos said he couldn’t share too many details about what made investigators suspicious, but described the house, in the southern part of Arizona, as being in a state of disarray that was unusual. He said Nancy Guthrie would not have been able to disappear on her own. 

“She is very limited in her mobility. We know she didn’t just walk out of there,” he said. “She did not leave on her own. We know that.” 

Savannah Guthrie, one of Nancy’s daughters, is the famed host of the NBC staple, the “TODAY” show. Nanos said Savannah had arrived in Pima County Monday after learning of her mother’s disappearance. 

When asked by reporters if Nancy had been targeted because of her daughter, Nanos said it was unclear but that Savannah Guthrie had not received any kind of threats and was in communication with the sheriff’s office. 

“All of the family has been very cooperative with us,” he said. “Savannah has been in touch with us as well. Our hearts go out to them.” 

Nancy Guthrie is not the kind of person to wander, authorities said. While her age causes mobility issues, she is as “sharp as a tack,” Nanos said. 

Nanos said his department was conducting door-to-door searches and asking anybody in the area to come forward, especially with any street-facing camera footage that may have captured a suspicious person or vehicle in the area. 

On Monday’s edition of TODAY, Savannah Guthrie issued a statement about her mother’s disappearance, which was read by her co-anchors, thanking supporters for their well wishes and asking anybody with information to come forward. 

“On behalf of our family, I want to thank everyone for the thoughts, prayers and messages of support. Right now, our focus remains on the safe return of our dear mom,” she wrote. “We thank law enforcement for their hard work on this case and encourage anyone with information to contact the Pima County Sheriff’s Department at: 520-351-4900.”