As the investigation into the disappearance of Savannah Guthrie’s mother, Nancy, hits the one-month mark, authorities aren’t giving up hope.

“I think the investigators are definitely closer,” Pima County Sheriff Chris Nanos told NBC’s Liz Kreutz in a Tuesday, March 3, interview with Today.

“We’ve got a lot of intel, a lot of leads,” Nanos added of the search for the 84-year-old, who was reported missing on February 1. “Now it’s time to go to work.”

While a lot of information has been released to the public in the hopes of eliciting tips, Nanos revealed that there are details that investigators have kept private.

“There’s so much that everybody wants to know, right? But I would be very neglectful and irresponsible as a police law enforcement leader to share that with everybody,” he explained. “We have information on this case that we think is hopefully going to lead us to solving this case, but that takes time.”

Kreutz asked about some recent developments that have been made public, specifically footage of a car seen on a doorbell camera near Guthrie’s residence on the day of her disappearance.

“What I would tell you is this. We’re aware of it and we’re looking into it,” he said. “Just like any other piece of evidence.”

They haven’t been able to identify the vehicle in the video, he added, but assured viewers that they’re looking into it, “as well as hundreds of thousands of other vehicles that were driving out that day.”

Authorities have urged anyone with information about Nancy’s disappearance to contact the FBI at 1-800-CALL-FBI (1-800-225-5324). You may also contact your local FBI office, the nearest American Embassy or Consulate, or you can submit a tip online at tips.fbi.gov.