The search for Nancy Guthrie, the 84-year-old mother of Today show host Savannah Guthrie, took a more troubling turn this week after purported ransom notes were sent to multiple media outlets.

Authorities said two notes with similar language have surfaced, though investigators have not yet confirmed their authenticity or whether they are directly connected to Guthrie’s disappearance, CNN reported.

The sheriff of Pima County said Tuesday that investigators are taking the notes seriously and are “absolutely not” dismissing them as part of the ongoing investigation. Officials declined to release details about the contents of the messages, citing the sensitivity of the case.

“When the note comes to us, it’s like any piece of evidence,” Sheriff Chris Nanos told CBS News. “You give it to us. You give us a lead. We’re going to look at every aspect of that lead and work it as a lead.”

One alleged ransom note was sent to the entertainment site TMZ on Tuesday.

The note “demands a specific substantial amount of Bitcoin … the amount is in the millions, and the note demands the cryptocurrency be sent to a specific Bitcoin address,” TMZ reported.

“There is a deadline connected to the alleged ransom … and an element of ‘or else,’” TMZ reported. The note indicated that an item in Nancy Guthrie’s house was damaged. TMZ reported that the note was submitted to the Pima County Sheriff’s Office but did not disclose which item was affected.

The sheriff’s department also responded to reports that a ransom note had surfaced.