A woman from Texas is facing a lengthy prison sentence for subjecting her stepdaughter, a middle-school student, to severe abuse, including chaining her to a locked bedroom and compelling her to scavenge through trash for food.

Marianna Miles, 46, received a sentence of up to 70 years in prison on Friday after being found guilty by a jury of causing serious mental injury to a child, as reported by the McLennan County District Attorney’s Office.

After the girl’s biological parents were incarcerated on unrelated charges, Miles assumed custody of her stepdaughter and her four brothers. The authorities launched an investigation in 2022 when Miles enrolled the girl at Connally Junior High School in Elm Mott, near Waco.

During a meeting with school officials, Miles described the girl as having “severe behavior problems” and insisted she needed constant supervision. She also claimed the girl was not to eat anything without her “explicit approval,” according to prosecutors.

However, school officials were more alarmed by Miles’ treatment of the child, particularly when they observed the girl to be “well-behaved and polite” despite appearing “unkempt and inadequately dressed.”

Prosecutors noted that educators observed the girl was noticeably thin and perpetually hungry, to the extent that she resorted to searching through garbage cans for sustenance.

Then in October 2022 a teacher noticed an injury to the child’s face. At first, the girl was hesitant to say what happened but then pointed the finger at Miles, saying her stepmom beat her with a belt buckle. The teacher alerted Child Protective Services and the Lacy Lakeview Police Department.

Authorities visited Miles’ home and discovered the girl was forced to stay in a “sparse” bedroom with no mattress and an alarm on the door that would go off if she tried to leave the room. According to a courtroom report from local CBS affiliate KWTX, the girl testified that Miles would force her to stay in her room for up to 20 hours during the pandemic.

Not only would Miles beat her, but the stepmother would also force the victim’s brothers to beat her.

“Miles also bound the child in both duct tape and, ultimately, heavy chains,” prosecutors said.

The suspect initially denied using chains on the girl but CPS investigators found the them inside the home. A child psychologist testified at trial that the girl suffers from post-traumatic stress disorder.

Miles reportedly testified she restrained the girl because she would often run away, attempted suicide three times and was a threat to the younger siblings.

“Our greatest privilege as prosecutors is to hold accountable those who perpetrate evil against those who are most vulnerable,” Tara Avants and Will Hix, assistant district attorneys, said in a statement. “This case exemplifies that. If convicted criminals were treated in the manner that Marianna Miles treated this child, prison authorities would be subject to prosecution. We are grateful to the real-life superheroes at Connally Junior High School, CPS and the Lacy Lakeview Police Department who made it possible to bring justice to an offender who earned every minute of her 70-year sentence.”

By law, Miles will be eligible for parole after 15 years. Prosecutors said they plan to object to her parole when she is eligible.

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