In Nancy Guthrie's investigation — along with camera footage and other evidence — investigators have ransom notes to analyze for clues to nab the presumed captors.

The notes — two in number — were released by the Pima County Sheriff's Department in July in the hope of someone recognizing the sender's "unique linguistic style."

But in the age of artificial intelligence, is it possible the alleged kidnappers used AI to generate the note?.

According to retired Colorado investigator Lisa Miller, she doesn't think that's the case.

She pointed to a typo in the notes that is contrary to generally error-free, AI-generated content.

Rather, Miller explained to Fox News, "There's something else, it's called idiolect."

"Idiolect is our personal style of communication, and it can be affected by many things. The region we grew up in, neighborhoods we live in, slang that we've adopted."

Additionally, the expert pointed to the sender’s unusual word choice. 

For example, 'perished' and not 'died' and describing Nancy as having been “buried in nature.”

These phrases, and the overall notes Miller flagged, led the expert to believe it was written by the same person.

Meanwhile, Nancy has been missing for six months, and no suspect has been arrested yet in her reported kidnapping.