Investigators combing a creek in rural North Carolina recovered evidence that could provide "valuable information" in the case of missing 10-year-old Zahra Baker.

The Hickory Police Department said in a statement sent to FoxNews.com that search teams recovered evidence on Wednesday but declined to elaborate on what was found.

A local television station reported Thursday that police discovered human remains in their search for Zahra, of Hickory, N.C., a bone cancer survivor who used a prosthetic leg and hearing aids. 

Citing police sources close to the investigation, wcnc.com reports that the remains, which have not been identified, are being sent to the North Carolina State Bureau of Investigation's lab.

A team of 40 investigators -- accompanied by a medical examiner -- searched the water and ground surrounding Gunpowder Creek in Caldwell County on Wednesday.   

Zahra was reported missing on Oct. 9 by her father, Adam Baker, under what police have described as suspicious circumstances. Authorities believe that the girl is dead.

Zahra's stepmother, Elisa Baker, is jailed on an obstruction of justice charge. Investigators say she admitted writing a bogus ransom note found at the scene of a fire in the family's backyard on the day Zahra was reported missing. A Catawba County grand jury indicted her on the charge last week.

The 42-year-old woman is cooperating with authorities, sources tell FoxNews.com. 

Investigators recovered a bone last week near a home in Caldwell County where the girl once lived with her father and stepmother. They believe that the bone, which is still undergoing testing, is Zahra's. Police also found a prosthetic leg in some brush that it is confirmed to have belonged to the girl.

Adam Baker and his daughter moved from Australia to North Carolina after he wed Elisa Baker, whom he met on a social networking website. 

The Charlotte Observer reported Thursday that Zahra's biological mother, Emily Dietrich, is en route from Australia to North Carolina. Dietrich has had no contact with the girl since she was a baby, according to the newspaper.

"I felt robbed before she was taken. Now I just feel broken," Dietrich reportedly told Australia's Channel 7 News.

Click here to read more on this story from the Charlotte Observer 

FoxNews.com's Cristina Corbin and The Associated Press contributed to this report