NBC Today co-host Savannah Guthrie has issued a public plea for anyone with information about her missing mother to come forward, after investigators released two ransom notes that lay bare the details of an abduction that began six months ago.

Nancy Guthrie, 84, was reported missing on 1 February. Authorities believe she was taken from her Arizona home. In her message, Savannah Guthrie described being woken and pulled from her bed in the dead of night when she learned of her mother's disappearance, according to The Hollywood Reporter.

The Pima County Sheriff's Department released the two ransom notes on 31 July. The notes had been received by local media outlets in Tucson, Arizona, in the days after Nancy Guthrie vanished, ABC News reported.

The first note opened with a direct address to Savannah Guthrie and the programme she anchors. "Hello Savannah, We have your mother Nancy," the note began, as published by NewsNation. It demanded between $4 million and $6 million in bitcoin for her release.

A second ransom note claimed that Nancy Guthrie died of heart issues shortly after she was abducted, NewsNation reported.

In her public message, Savannah Guthrie pleaded for anyone with information to come forward. She stated that a reward remains available and that tips can be provided anonymously.

No arrest has been announced. The Pima County Sheriff's Department has not publicly confirmed the validity of the claim made in the second ransom note regarding Nancy Guthrie's death.

For a family, six months without answers is its own kind of sentence. The release of the ransom notes puts the details of a private ordeal into public view, and with them, a renewed call for anyone who knows something to say so.