Authorities investigating the disappearance of Nancy Guthrie are facing significant challenges in retrieving additional surveillance footage from her Arizona home, with the sheriff leading the case acknowledging that the odds of obtaining more critical video appear low.

Guthrie, 84, the mother of “Today” show host Savannah Guthrie, had several security cameras installed at her residence outside Tucson. So far, however, investigators have managed to secure only Google Nest footage from the front of the property, which shows a masked individual walking up to her front door.

Pima County Sheriff Chris Nanos said detectives have repeatedly contacted Google in an effort to determine whether more footage can be accessed. Despite those efforts, the company indicated that further recovery may not be possible. “We don’t think we can get anything,” the sheriff told NewsNation on Tuesday.

Complicating matters, Nancy did not maintain an active subscription for her camera system, a factor that has made the retrieval process particularly complex, Nanos said.

“It’s like peeling paint — you have images over images over images. And you’ve got to peel back very easy because you might destroy the layer you wanted,” the sheriff explained.

Even so, Nanos expressed hope that any additional video, if recovered, could prove crucial in locating Nancy. Footage released to the public last week has already prompted nearly 5,000 tips from concerned citizens.

The investigation has now entered its 18th day as search efforts continue.

Despite the obstacles, the sheriff said he has “100% faith” that law enforcement will ultimately solve the case.

“If you were the guy, if you were that monster, you should be worried,” he said.

Officials have announced a reward of up to $100,000 for information that leads to Nancy’s safe return or results in the arrest and conviction of those responsible.

In a further setback Tuesday, authorities revealed that DNA evidence collected from a glove discovered roughly two miles from Nancy’s home did not produce a match in the FBI’s national DNA database, known as CODIS.