CHARLOTTE, N.C. (AP) – A North Carolina woman pleaded guilty Monday to killing her 15-month-old niece in a case in which social workers are accused of ignoring, then covering up the child’s abuse until after her death.

Ladybird Powell, 39, of Bryson City, appeared in Swain County Superior Court, where she pleaded guilty to involuntary manslaughter, extortion, possession of drug paraphernalia and two counts of felony child abuse.

Judge James Downs sentenced Powell to 12 years in prison.

She was arrested and charged with second-degree murder in January 2012 – one year after Aubrey Littlejohn’s death.

Powell had begun taking care of Aubrey shortly before the toddler’s mother, Jasmine Littlejohn, reported to jail in April 2010 to await trial in a marijuana-trafficking case. Littlejohn was in jail when her daughter died.

The plea is the latest development in a case that has stunned and polarized western North Carolina and sparked anger in the Native American community.

Aubrey was a member of the Eastern Band of Cherokee Indians, some of whom say the Swain County Department of Social Services did not do enough to protect Aubrey and other Native American children. Part of the Cherokees’ sprawling reservation lies in Swain County.

Two Swain County social service workers have been charged with falsifying records and indicted on obstruction of justice charges in Aubrey’s death. The DSS director at the time of the girl’s death was fired for what county officials said were unrelated reasons.

Before Powell’s arrest, an Associated Press investigation found that police and social workers had been aware of reports that Aubrey was being mistreated while she was staying with the woman.

David Wijewickrama, a lawyer representing Aubrey’s estate, called Monday’s events “a step, an important one, in the journey of justice for the Littlejohn family.” He has filed two lawsuits in connection with her death, at least one of which names the county DSS as a defendant along seven current and former social workers.

Wijewickrama thanked private detective Daniel Cheatham, who looked into the girl’s death, as well as Cherokee Principal Chief Michell Hicks, for demanding an investigation.

Wijewickrama said the next step will be to “bring justice to those employees of Swain County’s Department of Social Services, who may have contributed to her death and were involved in the shameless cover up of their own failures to protect this loving and innocent child from abuse.”

DSS officials said they’re prohibited from commenting on the case.

During Monday’s court hearing, Littlejohn cried as she listened to prosecutors discuss details of the case – including how Powell had snapped and broke the little girl’s arm. Later, Littlejohn addressed the court: “I miss Aubrey every day,” she said.

Members of Littlejohn’s family, led by great-aunt Ruth McCoy, had repeatedly pushed for justice in the case along with the little girl’s mother.

They say they complained repeatedly to DSS that Aubrey had bruises while she was staying with Powell, but that social workers ignored their pleas.

In one instance, McCoy, a realty officer for the Bureau of Indian Affairs, said she told authorities that she was worried about Aubrey and the toddler’s cousin, an 11-year-old boy also living with Powell.

McCoy accompanied sheriff’s deputies and social workers to Powell’s home the night of Nov. 9, 2010, to investigate a complaint that Aubrey and the 11-year-old boy were in danger and that Powell’s trailer had no heat.

They removed the boy, placing him in McCoy’s custody, but let Aubrey stay. The heat was off because the power bill wasn’t paid.

McCoy told the AP that she begged social workers to take Aubrey that night, but they wouldn’t listen.

The girl died Jan. 10, 2011, after Powell rushed her to the emergency room. When Swain County investigators looked into the case, they discovered the agency had at least three reports of neglect or abuse regarding Aubrey.

Investigators later found pages missing from written reports on the case.

Prosecutors say that after Aubrey’s death, a social worker ordered a subordinate to falsify records to make it appear that the department had done a thorough job investigating allegations that Aubrey was being abused.