Nancy and Savannah Guthrie on Today on April 17, 2019

Nancy and Savannah Guthrie.Credit : Nathan Congleton/NBCU Photo Bank/NBCUniversal via Getty

Authorities investigating the kidnapping of Nancy Guthrie are reportedly focusing on surveillance footage from two key dates leading up to her disappearance.

Since Feb. 1, investigators with the Pima County Sheriff’s Department and the FBI have been canvassing the Tucson, Ariz., neighborhood where the 84-year-old mother of journalist Savannah Guthrie was last seen the night before. Authorities believe she was taken against her will in the middle of the night.

On March 16, NewsNation’s Brian Entin reported on X that neighbors said investigators were asking about surveillance footage from Jan. 11 and Jan. 24.

Requests for surveillance footage by investigators are not new in this case. In early February, PEOPLE reported authorities had reached out to Ring doorbell camera users located near Nancy’s home for footage from specific dates, including one 20 days prior to Nancy’s kidnapping.

At the time, investigators requested footage from Jan. 11 between 9 p.m. and midnight as well as footage from Jan. 31 between 9:30 a.m. and 11 a.m. Those requests came after surveillance footage shared by the FBI and Pima County Sheriff’s Department showed a masked and armed person at Nancy’s front door in the early morning hours of Feb. 1.

The person has been described as a “male, approximately 5’9” – 5’10” tall, with an average build,” wearing a “black, 25-liter ‘Ozark Trail Hiker Pack’ backpack,” per an FBI post on X.

The search for Nancy has entered its seventh week, and no suspects or persons of interest have been identified.

Pima County Sheriff Chris Nanos previously ruled out Nancy’s relatives as suspects and said in a March 3 interview with NBC’s Liz Kreutz, which aired on the Today show, “I think that investigators are definitely closer. We’ve got a lot of intel, a lot of leads, but now it’s time to just go to work.”

In a previous statement to PEOPLE, a spokesperson for the Pima County Sheriff’s Department said investigators are looking into the possibility that the person may have had an accomplice.

Additionally, investigators are continuing to analyze DNA evidence collected from Nancy’s home and have noted that blood found on the exterior porch matches Nancy’s DNA. Nanos has said investigators remain hopeful it will lead investigators to “somebody.”

Since their mother went missing, Savannah, 54, and her siblings have been awaiting any word about what happened to her.

In a video posted to Instagram on Feb. 24, Savannah said her family has been “fearing for [Nancy] and aching for her and most of all just missing her.”

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A $100,000 reward had been offered by the FBI for any information leading to Nancy’s recovery or an arrest in the case. Savannah and her family have since offered an increased $1 million reward and donated $500,000 to the National Center for Missing & Exploited Children.