The FBI is investigating ransom notes related to the disappearance of Nancy Guthrie. Some of these notes have been deemed extortion attempts and have been discounted by the agency.

However, the FBI is still evaluating other ransom notes to determine their legitimacy. The total number of ransom notes received by the agency has not been specified.

For more information on the investigation, readers can refer to the original source, which may provide further details on the case and the FBI's ongoing evaluation of the ransom notes.