Guthrie, 84, was reported missing Feb. 1. Her family offered a $1 million reward this week for her recovery.

Law enforcement is preparing to return Nancy Guthrie’s Arizona home to her family, sources say, as the search for her is in its fourth week.

Guthrie, 84, the mother of “TODAY” show co-anchor Savannah Guthrie, was reported missing Feb. 1.

For weeks, her home in the Tucson area has been the center of a flurry of law enforcement activity — including the recovery of DNA evidence. Activity seen Wednesday is related to efforts to turn the home back over to the Guthrie family, two federal law enforcement sources told NBC News.

Officials acknowledged that law enforcement no longer sees the need to seal the premises as a crime scene or restrict the family from entering.

It was not immediately clear what the FBI or the Pima County Sheriff’s Department was doing inside the home Wednesday. It did not appear that they were engaged in activities outside the home that were seen on previous visits, which included testing or retracing their steps.

More than 23,000 calls have been made to the FBI tip line since Guthrie was taken, 750 of which came in the first 12 hours after Savannah Guthrie offered a $1 million reward Tuesday on Instagram, a senior official familiar with the investigation told NBC News.

Guthrie was last seen around 9:45 p.m. Jan. 31 after dinner at her daughter Annie Guthrie’s home, according to Pima County Sheriff Chris Nanos. She was reported missing the next day when she did not show up to watch a virtual church service with friends.

Authorities have not identified a suspect in her possible abduction.

The FBI on Feb. 10 released photos taken from Guthrie’s Google Nest camera that showed a masked, armed man later described as a suspect outside her home the morning she vanished. In that clip, the person appeared to tamper with the camera.

Most of those images showed a masked person with a backpack. But one did not, showing the person in dark clothing with a mask and gloves without a backpack.

On Monday, two law enforcement sources familiar with the investigation said that the image without the backpack was captured earlier, not the morning of her disappearance.

The FBI declined to comment on possible dates tied to the image. The sheriff’s department said Monday that there was no date or time stamp associated with that image and that any suggestion that it was taken on a different day is “purely speculative.”

Nanos said officials believe the majority of those images were from Feb. 1 only because they show the doorbell being disconnected.

The sheriff’s department and the FBI continue to actively pursue “all viable leads,” the department said Tuesday evening.

DNA evidence has been collected from Guthrie’s home and related search locations and submitted for forensic analysis, the sheriff’s department has said. Testing thus far has yielded no results.

Nanos has said mixed DNA was recovered from her home, meaning a DNA sample that contains genetic information from at least two people, but there have been challenges with those samples.