All of the ransom notes linked to Nancy Guthrie were fake, the FBI has said.
The 84-year-old mother of beloved US television host Savannah Guthrie has been missing from her Arizona home ever since the beginning of February.
Several notes were sent to US media outlets immediately after her disappearance.
But now, a senior FBI official has said none of the chilling notes are believed to be real.
The FBI official anonymously told Reuters of the development, with a second official verifying the claim.
Three notes were sent to outlets giving some information on Mrs Guthrie's whereabouts.
The first two notes have been determined to belong to the same individual, the FBI official said.
The first note required a sum "in the millions" and set two deadlines of February 5 and February 9, according to TMZ.
Nancy Guthrie (right), the mother of US Today show host Savannah (left), has been missing since the beginning of February
| REUTERSJust last week it was revealed the second note - also sent quickly after the 84-year-old's disappearance - claimed she died.
According to NBC News - the same network which broadcasts Savannah Guthrie's "Today" show - the second note did not ask for money and expressed regret for her passing, but did not directly apologise for her death.
A small deposit of cryptocurrency was placed by the FBI in the account associated with the first note, the official said.
But none of the money was withdrawn - leading officials to believe both the first note and linked second note were hoaxes.
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| FBI VIA REUTERSThe FBI official also said the recently-revealed third note, which claimed to know the identities of Mrs Guthrie's kidnappers and to have video of the "main guy" involved in the incident, is fake.
The official did not detail how it was determined the third note was fake.
Last week Savannah paused her show to appeal to the public for answers.
Savannah admitted that she was still in "agony" over her mother's disappearance.
Tributes left outside the Tuscon, Arizona, home of Nancy Guthrie
|REUTERS
The Guthrie family has offered a $1million reward for information which leads to the recovery of her mother, which Savannah reminded the audience of.
In February, disturbing doorbell camera footage of Mrs Guthrie's suspected abductor wearing a ski mask was released.
There were hopes a DNA test of a glove found near the Tuscon, Arizona, home would give investigators their next lead.
But samples taken from the glove failed to find a suspect in existing DNA databases.
Savannah has previously said her family still hope her mother is alive, but admitted she "may already be gone".