The Arizona sheriff investigating the kidnapping of Nancy Guthrie said in a new interview that authorities believe they know the motive.

In the NBC News interview published on Thursday, March 12, Pima County Sheriff Chris Nanos shared more about the investigation as the mother of Today co-host Savannah Guthrie remains missing.

Pima County Sheriff, Chris Nanos Nancy Guthrie

Pima County Sheriff Chris Nanos; Nancy Guthrie.Jan Sonnenmair/Getty; Nathan Congleton/NBC via Getty

“We believe we know why [the kidnapper] did this and we believe that it was targeted, but we’re not 100% sure of that,” Nanos said. “So it’d be silly to tell people, ‘Don’t worry about it. You’re not his target.’ You could be. Don’t think for a minute that because it happened to the Guthrie family, you’re safe. No. Keep your wits about you.”

The sheriff declined to elaborate further on a possible motive, saying, “I think it’s come out from day one. I think day one, we had some strong beliefs about what happened and those beliefs haven’t diminished.” He added, “I’m not going to get into those theories. We have our beliefs. Everybody else has theirs.”

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Nanos said investigators remain hopeful that the “mixed” DNA found at Nancy’s Tucson, Ariz., house will lead investigators to “somebody.”

The search for Nancy is nearly in its seventh week and no suspects or persons of interest have been identified.

The FBI and Pima County Sheriff’s Department have pointed to surveillance footage that appears to show a masked, armed person tampering with her doorbell camera on the morning of her kidnapping on Feb. 1.

That suspect has been described by the FBI’s Phoenix office as a “male, approximately 5’9” – 5’10” tall, with an average build.” In the clip, the person is wearing a “black, 25-liter ‘Ozark Trail Hiker Pack’ backpack,” per an FBI post on X.

In a statement to PEOPLE on Thursday, Feb. 19, a spokesperson for the Pima County Sheriff’s Department said investigators are looking into the possibility that the person may have had an accomplice.

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Savannah Guthrie and mother Nancy Guthrie

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Nancy Guthrie, Sheriff Chris Nanos

The Pima County Sheriff’s Department and FBI were recently seen canvassing the neighborhood. Several neighbors said investigators asked whether they experienced any internet service disruptions the night Nancy went missing, NBC’s Liz Kreutz reported on the Today show on Friday, March 6.

Nanos confirmed in Thursday’s interview that investigators were looking into the possible internet glitches.

The sheriff’s department had previously requested Ring camera footage from local homes.

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In a video posted to Instagram on Tuesday, Feb. 24, Savannah, 54, said her family has been “fearing for [Nancy] and aching for her and most of all just missing her.” She said the family is also donating $500,000 to the National Center for Missing and Exploited Children.

The FBI’s reward of $100,000 remains active.