Authorities searching for the body of Australian girl Zahra Baker began draining a pond near her father's workplace on Wednesday, while her stepmother remained in custody after appearing in court.
Authorities worked late into Wednesday night to drain the pond near a property owned by Real Tree Services, the tree trimming company where Adam Baker, Zahra's Australian father, is employed, The Charlotte Observer reported on its website.
Adam Baker and his wife Elisa, who is Zahra's American stepmother, remain suspects in the disappearance of the 10-year-old girl, who authorities believe has been murdered.
She was reported missing from her home in Hickory, North Carolina, on Saturday.
Elisa Baker appeared in court on Wednesday charged over a fake ransom note, while Adam Baker was reportedly on the scene as authorities searched for his daughter's body on Tuesday.
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About 15-25 investigators were working past nightfall on Wednesday in cool, damp weather to drain the pond, CNN reported.
The pond is next to the bushland owned by Real Tree Services that police and cadaver sniffing dogs searched on Tuesday night.
The search included inspections of mulching machinery and large piles of wood chips.
Zahra's father frequently worked there hauling loads of wood and brush to be fed into a wood chipper and turned into mulch, witnesses told CNN.
Adam Baker was on the scene during the Tuesday night search aimed at finding his daughter's body, Burke County Sheriff John T McDevitt told CNN on Tuesday night.
"He seems concerned," Mr McDevitt said.
"But I don't know how sincere his concern is."
Meanwhile, Elisa Baker, appeared in a US court on Wednesday, facing an obstruction of justice charge for writing a fake ransom note demanding $US1 million.
The note was found on a car windshield at the family's home in Hickory, North Carolina, at the weekend, before Zahra was reported missing.
Elisa Baker remains in custody on $US40,000 bail and her lawyer, D Scott Reilly, told the court he planned to file a motion to have the bond amount reduced in an attempt to win her release.
When judge Gregory Hayes asked Elisa Baker if she understood the charge against her and if she had any questions for him, she replied in quiet "yes" and "no" answers.
Mystery continues to surround the disappearance of Zahra, who had her lower left leg amputated five years ago after a battle with bone cancer. The cancer also resulted in Zahra needing hearing aids.
Lieutenant Becky Weatherman of the Burke County Sheriff's Office said the lack of specifics on where to look was making the search more difficult, the Observer reported.
"It's very hard," she said. "Especially if (someone) buried underground or you don't know where exactly to look."
The FBI has been called in to assist local police with the search and conduct any needed laboratory work.
Hickory locals held a candlelight vigil for Zahra outside East Hickory Baptist Church on Wednesday night.
