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TUCSON, Ariz. — The Pima County Sheriff's Department released a pair of ransom notes Friday in the hope that someone can identify the author.

Authorities have not yet confirmed that the notes are authentic, but Guthrie's daughter, "Today" co-host Savannah Guthrie, has said she believes they may be — and investigators haven't ruled them out either.

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Nancy Guthrie investigation continues, with a shot of Guthrie and an overhead her home

Authorities in Arizona are still searching for clues in the Nancy Guthrie case. The 84-year-old was last seen at his Tucson home on Jan. 31. (Getty Images)

They were sent on Feb. 2 and Feb. 6.

NEW DETAILS FROM NANCY GUTHRIE RANSOM DEMAND REVEALED, 'HER LIFE IS IN YOUR HANDS': REPORT

According to the sheriff's department, the two notes share a "unique linguistic style" and are believed to have been sent by the same person.

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The style is so distinct, that someone may be able to recognize the writer, authorities said.

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Anyone with information is asked to dial 1-800-CALL-FBI or, to remain anonymous, call 520-88-CRIME.

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This is a breaking news story.