A McLennan County jury delivered a sweeping rebuke to a Texas stepmother accused of turning her home into a prison cell for a middle-school girl, sentencing 46-year-old Marianna Miles to up to 70 years behind bars for injury to a child causing serious mental injury.

The verdict came after jurors heard harrowing testimony about a teenager who said she was chained, beaten, starved, and locked inside a barren bedroom for hours at a time.

According to the McLennan County District Attorney’s Office, Miles took custody of the girl and her four brothers after the children’s biological parents were sentenced to prison on unrelated charges. What began as a transfer of guardianship, prosecutors argued, devolved into years of abuse hidden behind a suburban front door.

The case first came to light in 2022 when Miles enrolled the girl at Connally Junior High School in Elm Mott, just outside Waco. During a meeting with school officials, Miles described the child as having “severe behavior problems” and insisted she needed to be “watched closely at all times.” She also told administrators the girl was not allowed to eat without her “express approval.”

Educators quickly grew concerned — not about the child’s behavior, but about her appearance. Prosecutors said teachers found the girl to be polite and well-behaved, yet visibly thin and often hungry. Staff members observed her rummaging through garbage cans in search of food. She was described as unkempt and inadequately clothed.

In October 2022, a teacher noticed an injury to the girl’s face. Initially reluctant to speak, the student eventually told authorities her stepmother struck her with a belt buckle. The teacher alerted Child Protective Services and the Lacy Lakeview Police Department.

When investigators visited Miles’ home, they discovered what prosecutors later described as a “sparse” bedroom where the girl was forced to stay. The room had no mattress. An alarm was attached to the door, designed to sound if she tried to leave.

In courtroom testimony reported by local outlet KWTX, the girl said she was made to remain in the room for up to 20 hours at a time during the pandemic. She testified that Miles not only beat her but also compelled her brothers to participate in the abuse.

Prosecutors alleged that Miles bound the girl with duct tape and, eventually, heavy chains. Although Miles initially denied using chains, investigators said they located them inside the home.

A child psychologist testified that the girl now suffers from post-traumatic stress disorder as a result of the abuse.

Miles took the stand in her own defense, claiming she restrained the child because the girl had run away, attempted suicide three times, and posed a danger to her younger siblings.

Jurors ultimately rejected that explanation.

“Our greatest privilege as prosecutors is to hold accountable those who perpetrate evil against those who are most vulnerable,” assistant district attorneys Tara Avants and Will Hix said in a statement. “If convicted criminals were treated in the manner that Marianna Miles treated this child, prison authorities would be subject to prosecution.”

Under Texas law, Miles will be eligible for parole after 15 years, though prosecutors have said they intend to object when that time comes.

The girl, now 16, is reportedly living with her mother and siblings in Killeen.