TUCSON, Ariz. — A single backpack has become a critical focal point in the investigation into Nancy Guthrie’s disappearance, prompting federal authorities to comb through Walmart sales records and store surveillance footage in search of a break.

Investigators are working with Walmart’s corporate security team while agents canvass stores across the Tucson metropolitan area, according to retired Supervisory FBI Agent Jason Pack, who described the strategy as a methodical effort to narrow the universe of possible suspects.

“They’re attacking this issue on several fronts,” Pack told Fox News Digital. “They are working with Walmart corporate security and simultaneously canvassing the stores in metro Tucson. Walmart should be able to trace back all sales of the backpack over a specific period of time. That will create many regional leads as agents track down and account for every single backpack. They’ll also want to recover video from the stores where they were sold.”

Authorities have not publicly detailed how many of the backpacks were sold or over what timeframe they are focusing, but the approach reflects a standard federal investigative technique. Fox News Digital has reached out to Walmart Corp. for additional information.

Former FBI agent John Nantz explained how anything that “ties a subject to the crime is critical in building a case for prosecution.”

Likening the purchase history analysis used in the conviction of Brian Cole Jr., who planted two live pipe bombs outside the Democratic National Committee and the Republican National Committee, Nantz said Cole’s arrest came after investigators developed critical evidence from his purchase history.

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Large retailers maintain SKU-level sales records that capture the date, time and location of each purchase, along with payment method information. 

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By isolating sales within a defined window, agents can create a list of purchasers and then prioritize leads based on physical descriptors.

Pack said retail forensics can be decisive when combined with other evidence.

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“When you can match a product to a person through both data and video,” he said, “you begin to shrink the suspect pool quickly.”

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Nancy Guthrie disappearance timeline:

Jan. 31, 2026

Between 9:30–9:45 p.m. — Family drops Nancy off at home

9:50 p.m. — Garage door closes (per authorities)

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Feb. 1, 2026

1:47 a.m. — Doorbell camera disconnects

2:12 a.m. — Security camera detects motion

2:28 a.m. — Pacemaker disconnects from phone application

11:56 a.m. — Family checks on Nancy after she misses weekly church livestream gathering

12:03 p.m. — 911 called

12:15 p.m. — Sheriff’s deputies arrive at home