NEWTOWN, Pa. (AP) — A Pennsylvania woman whose dismembered 14-year-old daughter's remains were found in the woods last fall has been charged along with her boyfriend with killing the girl in what officials are calling 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," said Bucks County District Attorney Matthew.

Sara Packer and Jacob Sullivan face nearly two dozen charges including criminal homicide, rape, kidnapping and abuse of a corpse over the July death of Grace, according to online court documents.

Jacob Sullivan was arraigned early Sunday; 41-year-old Packer was to be arraigned Sunday afternoon.

Sullivan, 44, apologized as he was led into court early Sunday, the Intelligencer newspaper reported.

"I'm sorry for what I did," he told reporters. "It was wrong."

Grace, who had been adopted by Sara Packer, was beaten, raped, poisoned and left for dead in a Quakertown attic, Weintraub said.

Sullivan choked the girl to death hours later when he found her still alive, he 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; K-9 teams found the legs and arms nearby, the criminal complaint said.

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attempts to contact Packer through August, on Sept. 7 investigators learned Grace and her younger brother had been withdrawn from Abington School District.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.

"When somebody goes missing, we expect people are going to work with us to try to identify that person, try to identify where she is. That didn't happen," Montgomery County District Attorney Kevin Steele said last month.

Authorities said Packer kept cashing her daughter's monthly $700 Social Security checks, and updated the disability forms in August without mentioning the girl's disappearance. It wasn't clear what Grace's disability was.

"After they murdered her, they maintained the pretense of Grace being alive so that they could continue to profit off of her existence," Weintraub said.

According to a criminal complaint, Sullivan and Packer made a suicide pact and attempted to overdose on prescription pills on Dec. 30. Both 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.

Sullivan was ordered held without bail.