(CNN) -- Authorities investigating the disappearance of a 10-year-old North Carolina girl have recovered "evidence that could provide valuable information" in the case, police said Thursday.
The evidence was located Wednesday, Hickory, North Carolina, police said in a statement, and will be analyzed at the North Carolina State Bureau of Investigation's lab.
Police launched a search for Zahra Baker October 9, but said no one other than a family member has reported seeing her since September 25, when a woman saw her at a furniture store.
Police did not elaborate or say what the evidence is. "We understand the concern and interest in this case by the public, but we must be cautious in prematurely releasing information, so it will not jeopardize any future criminal proceedings," police said.
Authorities said earlier this month a bone that might be related to the case was found. They also previously found a prosthetic leg belonging to Zahra, whose disappearance is being investigated as a homicide.
Elisa Baker, Zahra's stepmother, is jailed on charges unrelated to the girl's disappearance, as well as an obstruction of justice charge related to the case after she admitted to writing a fake ransom note found at the family's home.
Elisa Baker has said said she did not know what happened to Zahra, a freckle-faced girl who lost her leg to bone cancer at age 5 and reportedly developed lung cancer a few years later.
Zahra's father, Adam Baker, was arrested late last month in nearby Catawba County on eight charges, including five counts of submitting worthless checks and three counts of failing to appear in court.
Police earlier acknowledged that Adam Baker faced bad-check charges unrelated to the disappearance of his daughter. But they did not initially arrest him, as he had been helping authorities in their search.
Zahra's biological mother, Emily Dietrich, is coming to North Carolina from Australia, CNN affiliate WSOC reported. She could arrive sometime Thursday.
Last week, Dietrich told Australia's Seven Network that she had little hope of seeing Zahra alive again, according to WSOC.
Dietrich has not had contact with her daughter since Zahra was an infant.
Meanwhile, the Children's Protection Council of Catawba County said it will hold a candlelight vigil in honor of Zahra on Tuesday, her birthday. Toys or stuffed animals left at the vigil will be donated to the Cops for Tots organization, the group said in a statement.