“Maybe it’s weeks or months or years from now. But we won’t quit. We’re going to find Nancy. We’re going to find this guy,” Pima County Sheriff Chris Nanos said

Authorities in Arizona say they “won’t quit” when it comes to the search for Nancy Guthrie, but they admit it could take more time.

Speaking to The New York Times on Friday, Feb. 13, Pima County Sheriff Chris Nanos said his team of investigators is still determined to locate Nancy, 84, despite a number of dead ends in recent days.

“Maybe it’s an hour from now,” Nanos said, reflecting on the massive search. “Maybe it’s weeks or months or years from now. But we won’t quit. We’re going to find Nancy. We’re going to find this guy.”

Pima County Sheriff’s Department/X

Nanos’ comments come after the latest development in the investigation on Feb. 13, when authorities were seen swarming a residence near Nancy’s home late at night.

Shortly after police officers and vehicles descended on an area two miles away, the Pima County Sheriff’s Department (PCSD) confirmed to PEOPLE that the heavy law enforcement presence was tied to Nancy’s disappearance.

The following morning, on Saturday, Feb. 14, a PCSD spokesperson revealed that no arrests were made.

A federal, court-ordered search warrant, which a PCSD spokesperson said was “based on a lead we received,” was executed at a residence near E. Orange Grove Rd. and N. First Ave. in connection with the case.

A traffic stop was also conducted, and an individual was questioned. However, no arrests were made, the PCSD spokesman said, adding, “There are no further details available at this time.”

Brandon Bell/Getty

David Curl, who lives next door to the home searched on Feb. 13, told The New York Times that the residence belongs to an older woman who lives with her adult son. Curl said the “distraught” woman stayed the night at his home while investigators searched her residence.

“She had no idea what they were asking about,” he told the Times of his neighbor. “She had no information about the disappearance or any idea why they were focusing on their house.”

Brandon Bell/Getty

Want to keep up with the latest crime coverage? Sign up for PEOPLE’s free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.         

Nancy — who is the mother of Today show co-host Savannah Guthrie — was last seen at her Tucson home on the night of Jan. 31. Her family reported her missing around noon on Feb. 1 after she missed church.

Authorities executed the search warrant the same day that police announced that DNA evidence not belonging to Nancy or her “close contacts” was found at her home.

“DNA other than Nancy Guthrie’s and those in close contact to her has been collected from the property,” the PSCD said in a statement to PEOPLE on Feb. 13. “Investigators are working to identify who it belongs to. We are not disclosing where that DNA was located.”

Police previously said blood was discovered on the exterior porch of Nancy’s home that matches her DNA, and that gloves and other pieces of evidence tied to the case are undergoing forensic analysis.

The FBI also released surveillance footage of a masked and “armed” person appearing to tamper with a Nest camera at Nancy’s front door on the morning of her kidnapping.

In an Instagram post minutes after the new photos were released, Savannah, 54, shared the images and wrote: “We believe she is still alive. Bring her home.”

Shortly after, Savannah shared a second post on social media featuring video of the individual. “Someone out there recognizes this person,” she wrote, adding of her missing mother, “We believe she is still out there. Bring her home.”

Ransom notes tied to Nancy’s disappearance have since been allegedly sent to several media outlets. The FBI has said those are being investigated and that they are not aware of any communication between the alleged kidnapper(s) and the Guthrie family.

The FBI is now offering a $100,000 reward for any information leading to Nancy’s recovery or an arrest in the case.