NEWTOWN, Pa. (AP) — A woman whose teenage daughter’s dismembered remains were found in the woods last fall has been charged along with her boyfriend with killing the girl in a “rape-murder fantasy” the couple shared, a prosecutor said Sunday.

“The hours and the days leading up to her murder were probably the most horrible and traumatic that any person should ever have had to experience,” Bucks County District Attorney Matthew Weintraub said.

Sara Packer and Jacob Sullivan face charges including criminal homicide, rape, kidnapping and abuse of a corpse over the July death of 14-year-old Grace Packer, online court documents show.

On the morning of July 8, Grace, who had been adopted by Sara Packer, was taken to the attic of a house the couple rented, where she was beaten and then raped by Sullivan as her mother watched, an affidavit said. She was then poisoned, bound and gagged and left for dead, Weintraub said.

When the couple returned hours later, they discovered Grace was still alive, so Sullivan choked her to death, Weintraub said. Sullivan told police it took much longer than he expected to strangle her, the affidavit said.

Investigators say the couple packed Grace’s body with cat litter to mask decomposition smells and stored it in the attic. Officials allege they dismembered the body in October after being scared by a police visit.

The girl’s torso was found by two hunters in a Luzerne County park on Oct. 31, and K-9 teams found the legs and arms nearby, the criminal complaint said.

Sullivan was arraigned early Sunday, and Sara Packer was arraigned later. They didn’t enter pleas, were denied bail and were expected to be transferred to Bucks County Prison.

Sullivan apologized as he was led into court, the Intelligencer newspaper reported.

“I’m sorry for what I did,” he said. “It was wrong.”

Packer had previously been charged with child endangerment and obstruction. Police say she provided misleading information to investigators when reporting that Grace was missing from their Abington home in July.

Authorities say after numerous unsuccessful attempts to contact Packer through August, on Sept. 7 investigators learned Grace and her younger brother had been withdrawn from Abington School District. The investigation later revealed Packer had moved to Quakertown without telling police, and her 12-year-old adopted son, Grace’s biological brother, had been enrolled in Quakertown School District.

Authorities said Packer kept cashing her daughter’s monthly $700 Social Security checks and updated disability forms in August without mentioning the girl’s disappearance. It’s unclear what the girl’s disability was.

Sullivan and Packer made a suicide pact and tried to overdose on prescription pills on Dec. 30, a criminal complaint said. They were hospitalized after being found by a woman who lived with them.

Prosecutors said Sullivan began confessing to the killing overnight Friday into Saturday to workers at the hospital where he was being treated.