(CNN) -- Arizona authorities on Monday arrested the mother of a 5-year-old girl last seen more than a month ago, a police sergeant said.
Jerice Hunter was "placed under arrest for child abuse directly related to her daughter, Jhessye Shockley," Glendale Police Sgt. Brent Coombs told reporters.
"Our investigators are still working diligently to locate Jhessye," he said. "This is a step down that path."
None of the leads about the girl's whereabouts has panned out, Coombs said. But he did say that information about her mother, Hunter, proved to "have substance to the investigation (and) have proven to be accurate, as far as we can tell."
Jhessye allegedly wandered out of her Glendale home on October 11, unnoticed by her 13-, 9- and 6-year-old siblings who were supposed to be watching her. Her mother contacted police, saying she did so after she couldn't find her daughter when she returned home from an errand.
The siblings were later interviewed separately by experts and have maintained they do not know what happened to Jhessye, Coombs said previously.
Soon after reporting the girl missing, Hunter pleaded for the public's help.
"Please bring my baby back. ... Her safe return is all I want," Hunter said last month. "She belongs to this family. ... She's somebody's child. Mine. Please bring my child home."
Since then, Hunter has "not been cooperative with respect to a polygraph" test, which police asked her to take, Coombs said Monday. He described Hunter as the "lone focus" in the investigation.
Still, he did not rule out that others might be involved.
"We're not so shortsighted to think that there may not have been an additional person or persons who may ... have helped," Coombs said.
The reward for information leading to Jhessye, as well as to those responsible for her disappearance, has increased to $25,000, Coombs said Monday.
Jhessye is described as a black female about 3 feet 5 inches tall, 55 pounds, with black hair in a ponytail and brown eyes. She was last seen wearing a white T-shirt, blue jean shorts and pink sandals.
Given the time that has passed, the police sergeant conceded, "We do not believe that it will be likely that we will find Jhessye alive."