A ransom note sent days after the 84-year-old mother of US presenter Savannah Guthrie was abducted from her home claimed she had died, according to investigators.

The note was one of two addressed to Nancy Guthrie's family and sent to news media in the days after her January kidnapping.

The first demanded millions in bitcoin for her release, but the second stated that she had died, according to sources cited by US media.

The note from the possible kidnappers reportedly stated they did not mean for her to die and included an apology to the family. The Pima County Sheriff's Department declined to comment on the contents of the notes, but said the investigation "remains active and ongoing".

On Tuesday morning, during her first appearance on NBC's Today show since news of the second ransom note dropped, Savannah Guthrie addressed the news as tears fell from her face.

The longtime television presenter again begged people with information to come forward: "Somebody knows something," she said. "We are in agony."

"This is a new story today that is on your radar, but this is the life we live every day," Guthrie added.

The BBC has contacted the FBI, which has with Pima County spent months investigating the elder Guthrie's mysterious abduction from her home near Tucson, Arizona.

"The Pima County Sheriff's Department continues to work closely with the FBI as investigators follow up on leads, review information, and pursue the facts surrounding this case," a spokesperson for the sheriff's department said.

The BBC's US partner CBS and other outlets reported on Monday that law enforcement had requested that media hold off publishing details of the notes while they investigated Guthrie's disappearance.

Nancy Guthrie vanished after being dropped off at her home by relatives on January 31. Concern grew when she did not go to a friend's house to watch a virtual Sunday church service the next morning.

An initial ransom note was sent the day after she went missing and demanded millions in bitcoin for her release.

It gave specific details about her home, as well as details about her bedroom and the home's surroundings, investigators told CBS.

The note was reportedly addressed to Savannah Guthrie. It was sent to multiple media outlets, including a local TV station which reportedly adhered to a police request not to disclose its contents.

It has only now emerged that a second note - sent on 6 February - used language similar to that of the first one, but did not include any demands, instead apologising for her death and stating it was inadvertent.

Authorities and Guthrie's family repeatedly issued public warnings that the elderly victim was in poor health and was without critical medication.

As the search continued, authorities released images of a masked person who was seen in security camera footage outside her home.

The Guthrie family had been offering a $1m (£760,000) reward, in addition to $100,000 pledged by the FBI, for information leading to Nancy Guthrie's return.

On 24 February, Savannah Guthrie said they would keep hoping, even though they "know that she may be lost, she may already be gone".

In a March interview with NBC, Guthrie said several ransom notes were sent, and she believed some of them were bogus. She also told the network her family believed the two initial notes were authentic.

Guthrie stepped away from NBC's Today show for more than two months while the investigation was underway. She returned to the programme in early April as the search continued.