TUCSON, Ariz. — As authorities continue investigating Nancy Guthrie’s disappearance, their attention may have zeroed in on time frames weeks before the 84-year-old vanished from her home.

A neighbor of Guthrie's told Fox News' Sarah Alegre investigators came to her door in person and requested video footage from Jan. 31.

In addition, the neighbor said a Ring app alert claimed investigators also were requesting surveillance footage from Jan. 11 from 9 p.m. to midnight local time and Jan. 31 from "9:30–11" without specifying a.m. or p.m. The alert also referenced a "suspicious vehicle on Via Entrada around 10 a.m. on Jan. 31."

The Pima County Sheriff’s Department told Fox News the Ring alert itself did not originate from PCSD, but rather from a resident who included links to the PCSD evidence submission site.

Former FBI agent John Nantz said when law enforcement narrows in on specific dates and a tight 90-minute window, it typically signals efforts to validate known movements and reconstruct a possible route.

When asked whether specifying times points to timeline validation or tracking a vehicle's movements, Nantz said, "They're likely piecing together a route."

Nantz added that targeted canvassing often follows the recovery of key surveillance footage, such as Ring video, as investigators seek to fill gaps and alert residents who may not realize they possess relevant evidence.

"It’s likely they’re canvassing since the Ring footage was recovered in case individuals may now realize they might be in possession of valuable evidence," he said.

Authorities have not publicly detailed what may have occurred during those windows. Fox News Digital has reached out to the Pima County Sheriff's Department for comment.

Guthrie’s family members say she was dropped off at home between 9:30 p.m. and 9:45 p.m. Saturday, Jan. 31. Her garage door closed at 9:50 p.m., according to authorities.

At 1:47 a.m. Sunday, Feb. 1, authorities say, the doorbell camera at Guthrie’s home disconnected, followed by a security camera detecting motion at 2:12 a.m. Her pacemaker disconnected from an application on her phone at 2:28 a.m.

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Family members checked on Guthrie at 11:56 a.m. after she reportedly did not attend a weekly gathering where she normally watched a livestreamed church service.

Authorities were called and arrived at her home shortly thereafter.

Fox News Digital's Peter D'Abrosca contributed to this report.