Elijah Lewis, the 5-year-old boy who vanished and was found dead in Massachusetts last month, died of “violence and neglect,” according to New Hampshire authorities. The child’s death has been ruled a homicide, John Formella, the state’s attorney general, said on Monday. A release from his office outlined how “facial and scalp injuries, acute fentanyl intoxication, malnourishment, and pressure ulcers” all contributed to Lewis’ death. The boy’s mother, Danielle Dauphinais, and her boyfriend, Joseph Stapf, remain in custody without bail on charges of witness tampering and child endangerment. They were arrested in New York City last month.

A cadaver dog discovered Lewis’ buried remains in the Abington woods after a joint search effort involving multiple agencies, including the FBI, across two states. The investigation into his disappearance began after a child welfare agency reported him missing on Oct. 14. Dauphinais apparently did not participate in notifying the authorities. Earlier this year, she texted a childhood friend a series of disturbing messages about her son, comparing him to serial killers like Ted Bundy and Jeffrey Dahmer. “I want him gone,” she wrote. “I can’t handle it anymore.”