Tucson, Arizona - TV anchor Savannah Guthrie said Tuesday her family is now offering up to $1 million for a tip leading to the recovery of her mother, who was kidnapped 24 days ago.

Guthrie acknowledged that her mother might now be dead, in what would be a tragic end to a case that has gripped America and baffled police since Nancy Guthrie (84) went missing from her home in Tucson, Arizona, on February 1.

Despite a frantic search for the older woman, police have not identified a suspect in the case.

Fighting back tears in a post on Instagram, Guthrie said she and her sister and brother now accept their mother may be dead.

"We know that she may be lost," Guthrie said. "She may already be gone."

But the family needs closure, she added.

"We need her to come home. For that reason, we are offering a family reward of up to one million dollars for any information that leads us to her recovery," Guthrie said.

"Someone out there knows something that can bring her home," Guthrie said. "Somebody knows."

Federal investigators are offering $100,000 for information leading to the older woman's location or the arrest of her captors.

The FBI has released photos and video of a masked person approaching Guthrie's home on the night of the kidnapping but has failed to identify a suspect.

Pima County Sheriff Chris Nanos said last week that investigators had ruled out Nancy Guthrie's family members as having any involvement in her disappearance.