It was the latest twist in an investigation that has gripped the nation since Nancy Guthrie disappeared on Feb. 1. Until Tuesday, it seemed authorities were making little headway in determining what happened to her or finding who was responsible.

Nancy Guthrie, mother of "Today" show host Savannah Guthrie, has been missing since February 1. Here's what we know about the case.

This latest development happened just hours before the Pima County Sheriff’s Department revealed they had detained and questioned a person in connection with the disappearance of Savannah Guthrie's

Nancy Guthrie disappearance prompts third alleged letter demanding one Bitcoin in exchange for information about any suspected abductors of the 84-year-old Tucson woman.

New surveillance video from the Tucson, Ariz., home of Nancy Guthrie, 84, shows a person at her front door early on the morning of Feb. 1, when she was abducted. The individual is wearing a ski mask,

Lord, God, bless and guide the authorities in their search for Nancy, give them wisdom along every step of the path to her,' her pastor said.

The big questions baffling investigators, law enforcement experts and the millions of Americans following the Nancy Guthrie case.