A Pennsylvania woman pleaded guilty Wednesday to the "horrific" abuse of her five adopted children. 

Stephanie Duncan, 43, of Annville, pleaded guilty to 30 charges related to the abuse of her and her husband’s five adopted children between ages 6 and 15. 

Prosecutors said she was the primary abuser, denying the children basic nourishment and subjecting them to brutal and graphic punishment, WHTM reported. Her husband, Robert Duncan, who did nothing to intervene, pleaded guilty and was sentenced last week to between six and 30 years behind bars.  

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"It was one of the most horrific scenes I’ve been to and knowing that it was suffered by children makes it that much worse," Lebanon County District Attorney Pier Hess Graf told Penn Live Wednesday. 

Graf described the conditions inside the home of the two child abusers. Graf said she sat down in the bare, frigid basement bedroom where an 11-year-old who received the most severe of the abuse was forced to sleep with no mattress. She said he was beaten and isolated, given barely enough food or water to survive. 

"I wanted to feel what it was like for that little boy on a daily basis for years," Graf said. 

(Lebanon County District Attorney's Office)

Appearing virtually before Lebanon County Judge Bradford H. Charles Wednesday, Stephanie Duncan entered an open guilty plea, which means there is no agreement regarding her sentence. 

Her sentencing is scheduled for Dec. 22, and Charles said Duncan could face up to 288 years in prison and $65,000 in fines on charges that include aggravated assault, endangering the welfare of a child and tampering with or fabricating physical evidence.

The judge chastised Robert Duncan for his apology to the court before his sentencing on Oct. 13. 

"The children will never recover psychologically," Charles said, according to the Lebanon Daily News. "There are times when an apology is trite, and this is one of those times. It takes a sociopathic sadist to torture children. It takes someone who has no regard for humanity to sit back and let it happen."

The abuse carried on for years in the couple’s home in North Annville Township until the 11-year-old was rushed to Penn State Health Milton S. Hershey Medical Center in January. Court documents say he was hypothermic with a core body temperature of 85 degrees. His blood pressure was unusually low, and the boy had bruises on his neck, shoulders, back, abdomen, hip and genitals. 

Prosecutors said the boy nearly died several times at the hospital and had "serious bodily injury" from physical abuse, as well as exposure to cold, significant fluid restriction and possible ingestion of a sodium-containing liquid such as diluted bleach, Penn Live reported. 

"Each child provided statements which also illustrated the disturbing experience of watching S. Duncan and R. Duncan physically attack his or her siblings," according to the district attorney's office. "Even minor misbehaviors, such as taking too long to consume water or complete a chore, resulted in horrific, violent abuse."

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The other children told investigators they were subjected to a sort of "caste system" and were required to complete hours of chores. Their schedules were regimented and their food was rationed. Alarms were placed on their doors and security cameras were placed in their bedrooms and a playroom.

Police said the abuse included beatings, strangulation and deprivation of food, water, heat and bathroom privileges, according to the Lebanon Daily News reported.