CONCORD, N.H. — A New Hampshire woman pleaded guilty Thursday to second-degree murder in the 2021 death of her 5-year-old son, who was beaten, starved and neglected, weighing just 19 pounds when his body was found buried in a Massachusetts park, prosecutors said.

Danielle Dauphinais, 38, faces 58 years to life in prison when she is sentenced next month. Dauphinais had been scheduled for a trial and initially pleaded not guilty before opting to change her plea. She also pleaded guilty to two counts of witness tampering in the death of her son, Elijah Lewis, in an agreement reached with prosecutors.

Judge Lisa English in Nashua accepted Dauphinais’ guilty pleas. Her lawyer said that although Dauphinais didn’t agree with all the facts presented by the prosecution, she did agree she participated in Elijah’s death.

The child was discovered missing and found dead in October 2021 in Ames Nowell State Park in Abington, Massachusetts. An autopsy showed he suffered facial and scalp injuries, acute fentanyl intoxication, malnourishment and pressure ulcers.

A doctor would have testified at trial that Elijah suffered “torture, repeated physical assaults, ongoing psychological maltreatment, including emotional rejection, denigration, isolation, and denial of care,” prosecutor Bethany Durand said.

Dauphinais’ boyfriend, Joseph Stapf, pleaded guilty to manslaughter, second-degree assault, falsifying physical evidence and witness tampering in 2022 in connection with the boy’s death. He was sentenced to 22 to 45 years in prison.

Durand read a series of texts from Dauphinais to Stapf in court that expressed hostility toward Elijah.

“He said he wants food and he wants me to stop starving him because it’s not nice,” one said. Another one read, “I’m gonna kill him and I mean it,” and another said, “I hit him with the shower rod that’s all I did.”

Elijah’s father, who lives in Arizona, had brought him to live with Dauphinais, Stapf and their 2-year-old daughter in May 2020. By that fall, the father had filed a complaint with the state Division for Children, Youth and Families, concerned that Elijah wasn’t getting proper medical care, Durand said.

A visit to the doctor that November showed the child weighed 32 pounds and had bruises on his face, eye and arm. Dauphinais later told the agency that her son was sent to California to live with Dauphinais’ sister, a custody arrangement the father had agreed to, but Dauphinais didn’t follow through, Durand said.

In October 2021, Dauphinais had given birth to a boy at home. Stapf brought the infant to a hospital with the intent to leave him there. The child services agency opened an investigation and could find no sign of Elijah. Dauphinais said her son was with her sister, and then her brother. Both later told investigators that Dauphinais had contacted them and asked them to lie about Elijah’s whereabouts.

Prosecutors said that when Elijah was found, he was 3 feet tall and weighed 19 pounds, while an average 5-year-old boy would be about 3.6 feet tall and closer to 40 pounds.

When Elijah was still missing, Stapf and Dauphinais were arrested in New York. Days after their arrest, Elijah’s remains were found.

Dauphinais was indicted in 2022 on one count of first-degree murder alleging that she purposely caused her son’s death, one count of second-degree murder alleging she acted recklessly in causing his death, and three counts of witness tampering.