“We have nothing else to go on but the belief that she is here, she’s present, she’s alive, and we want to save her,” Pima County Sheriff Chris Nanos told NBC during an interview.

The strong message came as the desperate search for 84-year-old Nancy Guthrie stretched into its fourth day.

However, Nanos’ department said Wednesday it does not have any suspects yet.

Two separate possible ransom notes were reportedly sent to news organizations Tuesday, although their exact contents and demands have not been released publicly.