July 2 (UPI) — Federal authorities said that some of the ransom notes they have received over the course of their investigation into the kidnapping of Today host Savannah Guthrie’s mother were not legitimate.

The FBI has received several purported ransom notes during its five-month investigation into the disappearance of 84-year-old Nancy Guthrie, who was reported missing from her Arizona home on Feb. 1.

In a statement Wednesday, the FBI’s Phoenix field office revealed that some of those notes “have been deemed to be extortion attempts without legitimacy” while others “may potentially be legitimate and are still being investigated as such.”

The statement seemed to be in response to recent reporting stating authorities believe notes from the purported kidnappers in February that claimed Nancy Guthrie had died and that they didn’t mean to kill her were authentic.

The reports referenced a note sent to local media on Feb. 2 demanding millions in ransom, and a second note from Feb. 6 that stated Nancy Guthrie had died.

On Feb. 7, Savannah Guthrie, appearing alongside her siblings in a video posted to Instagram, said to the kidnappers that “We received your message, and we understand.”

The FBI did not mention any specific notes.

The Pima County Sheriff’s Department, the lead investigating agency in the case, also issued a statement Wednesday, confirming that it has also received information regarding potential ransom notes without commenting further.

“Every tip and lead is taken seriously and is forwarded directly to our detectives, who continue to work in coordination with the FBI,” it said, directing further questions about ransom notes to the federal law enforcement agency.

The FBI said the investigation is ongoing.

“This case continues to be investigated as a kidnapping for ransom case,” it said.