Nancy Guthrie disappearance: Former CIA agent says one mistake could crack case

A "mistake" by abductors may be the key to finding Nancy Guthrie, according to cybersecurity experts who believe human error will eventually bypass the encryption used in ransom notes.

Nancy Guthrie disappearance: Day 9 latest updates

Feb. 9 marks the ninth day in the search for Nancy Guthrie, the mom of NBC "Today" show anchor Savannah Guthrie.

Nancy Guthrie disappearance: Day 8 latest updates

Feb. 8 marks the eighth day in the search for Nancy Guthrie, the mom of NBC "Today" show anchor Savannah Guthrie.

Nancy Guthrie disappearance: Day 6 latest updates

Authorities say Guthrie was taken from her home against her will and is without her necessary medication. She's described as being 5 feet 5 inches tall and 150 pounds, with brown hair and blue eyes.

DPS crew members killed in helicopter crash while responding to Flagstaff shooting

Two Arizona Department of Public Safety crew members were killed in a helicopter crash Wednesday night while responding to an active shooting incident in Flagstaff.

Nancy Guthrie disappearance: Day 5 latest updates

Nancy Guthrie was last seen on the evening of Jan. 31 at her home outside of Tucson. She was reported missing after her family members were notified that she hadn't shown up for church.

Guthrie family makes direct appeal to possible abductors as alleged ransom deadline passes

As the deadline for a reported ransom note expired, the Guthrie family posted a video to Instagram speaking directly to those they believe are holding their mother, Nancy Guthrie, 84.

Nancy Guthrie: Trump directs federal law enforcement to assist in Pima County search

President Donald Trump announced on Feb. 4 that he's directing "all federal law enforcement" to assist in the search for Nancy Guthrie, 84, who was reported missing from her Catalina Foothills home on Jan. 31.

Nancy Guthrie disappearance: Day 4 latest updates

Nancy Guthrie was last seen on the evening of Jan. 31 at her home outside of Tucson. She was reported missing after her family members were notified that she hadn't shown up for church.

Nancy Guthrie: Family seeks proof of life amid ransom note reports

In an emotional video, “Today" host Savannah Guthrie & her siblings pleaded for the return of their mother, Nancy Guthrie, 84, missing from Tucson since Jan. 31. Addressing ransom note reports, the family said they're “ready to talk" but demand proof of life.

Nancy Guthrie: Former FBI agent breaks down her 'very odd' disappearance

Authorities and the FBI are vetting leads in the "odd" disappearance of Nancy Guthrie, 84. While experts suggest the mother of Savannah Guthrie was targeted due to suspicious ransom notes, officials say a motive has not been confirmed.

Nancy Guthrie: Her disappearance doesn't appear targeted, PCSD says

Pima County Sheriff Chris Nanos said investigators believe 84-year-old Nancy Guthrie was taken from her Catalina Foothills home between Jan. 31 and Feb. 1 against her will, though officials currently found no evidence the incident was targeted.

Nancy Guthrie disappearance: Day 3 latest updates

Authorities say "concerning circumstances" at Guthrie's Catalina Foothills home suggest she was taken against her will, and was possibly kidnapped or abducted. Signs of forced entry were reportedly found at the scene.

Nancy Guthrie: Ransom note claim prompts sheriff to release a statement

Pima County Sheriff Chris Nanos said investigators believe Nancy Guthrie, 84, was abducted from her home Jan. 31. The FBI is assisting in vetting a potential ransom note while detectives analyze DNA recovered from Guthrie’s residence.

Timeline: NBC host Savannah Guthrie’s mother disappears as sheriff says she may have been 'abducted'

Officials in Tucson, Arizona, are continuing to search for the mother of NBC "Today" co-host Savannah Guthrie after she went missing from her home and was last seen on Saturday night, saying that a crime has been committed.

Savannah Guthrie asks for prayer as her mother remains missing: 'We need you'

Nancy Guthrie, 84, was last seen on Saturday evening at her residence near East Skyline Drive and North Campbell Avenue, north of Tucson, at around 9:30 p.m. after family members dropped her off, according to the Pima County Sheriff’s Department.

Nancy Guthrie: Tips wanted in case of missing mother of 'Today' show host Savannah Guthrie

Pima County Sheriff's Department homicide detectives are investigating the disappearance of Nancy Guthrie, 84, after her wallet and vehicle were found at her home Feb. 1. She is the mother of NBC "Today" anchor Savannah Guthrie.