United Kingdom, Feb. 16 -- Detectives have questioned if Nancy Guthrie could have been kidnapped as part of a "revenge" plot.

The 84-year-old mother of Today show host Savannah Guthrie has been missing since February 1, and the Pina County Sheriff's Department (PCSD) admitted they are struggling to find a motive for behind her disappearance.

Referring to a masked intruder captured on a security camera at Nancy's Tucson, Arizona, home, Pima County Sheriff Chris Nanos told the Daily Mail: "This is somebody who's disappeared from the face of the earth, and now we have a camera that says here's the person who did this.

"And that's what makes me say this is a kidnapping. The motivation for it is where we get stuck, right? Is it for money? I...