Nancy Guthrie has mobility issues and is without medication she needs, the sheriff said, pleading for anyone with information on her whereabouts to come forward.
She is of “sound mind … The family wants everybody to know this isn’t somebody who just wandered off,” Nanos told the press conference.
He would not go into detail about what evidence had been discovered at the home, saying only that investigators determined “we do in fact have a crime”.
Security cameras at the home were also being examined, he said.
Yesterday, he had said that homicide investigators were a part of the probe.
Savannah Guthrie, 54, is one of the top news personalities in the US and is co-host of NBC News flagship morning programme Today.
-Agence France-Presse