The Arizona house where authorities believe Nancy Guthrie, the mother of “Today” show co-host Savannah Guthrie, was abducted in the middle of the night will soon be returned to her family, a law enforcement source told CBS News.

The release of Nancy Guthrie’s home in Tucson comes nearly four weeks after she was reported missing on Feb. 1, sparking a massive search effort for the 84-year-old woman.

More than 1,500 tips have come into the FBI’s tip line since Nancy Guthrie’s family offered a reward of up to $1 million for information leading to her recovery, two law enforcement sources told CBS News.

Savannah Guthrie announced the family’s reward in an emotional social media video Tuesday as she renewed her plea for anyone with information in the case to come forward. The FBI is also offering a reward of $100,000.

In the video, Savannah Guthrie expressed hope that what she called a miracle will still happen nearly a month into the search, but she also acknowledged her mother “may be lost.”

“If this is what is to be, then we will accept it, but we need to know where she is,” Guthrie said. “We need her to come home.”

DNA recovered from Nancy Guthrie’s home may not yield a usable profile of the suspect, according to sources close to the investigation, with one source calling it “low-level.”

Bob Krygier, a retired Pima County Sheriff’s Department lieutenant, said the characterization of the DNA evidence as “low-level” meant to him that it’s “very difficult to work with.”

But sources said even a low-level sample can be enhanced by scientific techniques in the lab although it would take longer to achieve.

The sheriff’s department sent DNA evidence from the scene to a private lab in Florida instead of handing it over to the FBI. Sheriff Chris Nanos said he’s hopeful that the DNA will lead to a name.