Nancy Guthrie has been missing from her residence for almost four weeks in a case that has captivated the country and triggered an exceptional law enforcement operation.

The 84 year old mother of Today show presenter Savannah Guthrie was taken from her property on 1st February, with apparently minimal headway made in attempts to locate her despite a thorough and extensive investigation.

Pima County Sheriff Chris Nanos, who has been overseeing the search effort, has maintained throughout the enquiry that he believes Nancy remains alive. Sheriff Nanos has disclosed he stays optimistic and believes Nancy is being held in the vicinity.

"I just believe she's somewhere here locally," he added. "I don't know why."

This follows a mysterious individual who claimed to "see Nancy 5 days ago" providing disturbing fresh evidence.

From the beginning, Nanos has expressed measured hope, consistently emphasising that investigators are handling the case as an ongoing kidnapping. He confirmed authorities are pursuing every piece of information in an attempt to locate Nancy and return her home unharmed.

After the publication of security footage obtained from Nancy's doorbell camera, the Federal Bureau of Investigation were able to issue a description of the suspect as "a male between 5ft 9in and 5ft 10in," generating a substantial public response.

Information poured in from throughout the state and further afield as the case continued to draw nationwide interest. A combined reward of $200,000 is being provided by the FBI and the Tucson Crime Stoppers.

Sheriff Nanos revealed that up to 40,000 leads are being pursued by a team of 400 investigators, ensuring no detail is overlooked. Search squads, analysts and specialist units have all been mobilised as authorities tirelessly strive to trace Nancy's movements and pinpoint any potential suspects.

Nearly a month later, however, no definitive DNA matches have been identified either from the single black glove found two miles from Nancy's residence, which was analysed using the FBI's CODIS system, or from within Nancy's home, where "mixed" DNA samples necessitate extensive work to isolate a singular match.

A DNA breakthrough would significantly advance the search, providing authorities with the crucial development they urgently require. Officials have confirmed that Nancy's friends and family have been absolved of any suspicion, enabling investigators to redirect their focus.

In the meantime, Savannah has repeatedly made public pleas on social media, encouraging anyone with information to step forward.

In her most recent post on day 24 of Nancy's disappearance, she announced she was "offering a family reward of up to $1 million dollars," for information leading to the discovery of her mother's location.

In the heartfelt message, she acknowledged the possibility that Nancy "may already be gone," but maintained the family still clung to "hope against hope" for her return. "Someone out there knows something that will bring her home," she stated.