The sheriff involved in the search for Nancy Guthrie believe that "something occurred" on Jan. 11, three weeks before she disappeared from her Tucson, Ariz. home.

Authorities say they cannot share any evidence indicating the date's importance to their investigation.

Savannah Guthrie asked her followers for any information they may have about key dates in the timeline of Nancy's disappearance.

The sheriff involved in the search for Nancy Guthrie has new insight into the timeline of her disappearance.

On Monday, March 23, Pima County Sheriff Chris Nanos spoke to local news outlet KOLD, noting that there’s been speculation that one of the images released of the suspect was from a night other than Jan. 31, with some thinking it was Jan. 11. NewsNation’s Brian Entin had reported on March 16 that investigators were in search of footage and information from both Jan. 11 and Jan. 24.

Authorities looked into images that were released of the suspect that many believe may have been taken from a different night than Jan. 31. However, without timestamps, there's no way to confirm the date. "There's nothing there, critical that we can say positively say that this individual, with or without the backpack, was at that house, on Jan. 11," Nanos said.

Footage of the suspect removing the doorbell camera from Nancy's home is the only way that authorities know that the recording is from the evening she was abducted.

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However, authorities "do believe that something occurred on Jan. 11 and that's with the FBI's analysis of the equipment and digital stuff they've done," he added. Nanos noted that this information remains speculative and that they couldn't share any evidence that made law enforcement focus on this date.

Nanos also told the outlet that the investigation into Nancy's disappearance remains ongoing. "We have so much in front of us. And we believe we have good evidence in front of us," Nanos said. "Will that dry up? Could I be wrong? Absolutely. Anything is possible, but we’re not giving up."

This update comes days after Nancy's daughter, TODAY co-anchor Savannah Guthrie, asked her followers for any information they may have relating to Jan. 11 and the days surrounding her mother's disappearance.

"We desperately ask this community for renewed attention to our mom’s case," her statement on Instagram read. "Please consult camera footage, journal notes, text messages, observations, or conversations that, in retrospect, may hold significance. No detail is too small. It may be the key.”

"We hope people search their memories, especially around the key timelines of January 31 and the early morning hours of February 1, as well as the late evening of January 11," the statement added.

Nancy Guthrie was last seen on Jan. 31 at her residence in Catalina Foothills, Ariz. On Feb. 2, Nanos announced that the missing person case was being investigated as a crime and her home was officially declared a crime scene.

A public information officer for the sheriff's department told Entertainment Weekly at the time that "investigators believe she was taken from the home against her will, possibly in the middle of the night. Taken against her will includes possible kidnapping or abduction."

Nancy had no cognitive issues and her disappearance was "not dementia-related," said Nanos. However, she has mobility issues and "couldn't walk 50 yards by herself."

The Guthrie family has increased the reward for Nancy's return to $1 million. The Pima County Sheriff's Department and the FBI continue to urge anyone with tips to call 1-800-CALL-FBI.

Read the original article on Entertainment Weekly