The Bucks County man who has admitted to raping, killing, and dismembering Abington teenager Grace Packer returned to a Doylestown courtroom Friday to plead for his life before a jury that could decide otherwise.

Jacob Sullivan, 46, pleaded guilty to the crimes last month. Now, the jury of six men and six women is tasked with determining whether he will be sentenced to death or life in prison without the possibility of parole. The sentencing proceedings are expected to last as long as two weeks.

Sullivan’s girlfriend, Sara Packer, 44, Grace’s mother, also took part in the killing, authorities have said, and is expected to plead guilty in exchange for a sentence of life in prison after Sullivan is sentenced.

His lawyers, however, made clear on Friday that they planned to make Sara Packer a key part of Sullivan’s defense.

In a half-hour opening statement, public defender Jack Fagan told jurors to consider what he called Sara Packer’s controlling nature — in her relationships with her boyfriend and her adopted daughter — when deciding Sullivan’s sentence.

“Sara Packer was the driving factor in the intent, the planning, and the execution of what happened to her daughter,” Fagan said.

Fagan described Sullivan as a “quiet, shy, almost childlike" man who had a toxic relationship with his own mother and became dependent on Packer after they met online in 2013.

He said that while Sullivan did kidnap, rape, and choke to death Grace, and then dismember and disposed of her body, Sara Packer was the one who pulled the strings. She gave the teen a concoction of drugs, bought the tools used in her murder and dismemberment, lied to police, and picked the site where the teen’s body was dumped.

Bucks County District Attorney Matthew Weintraub, who is taking the unusual step of personally arguing the case, disagreed with the defense.

“The case is not Jacob Sullivan vs. Sara Packer,” he said in his opening statement. “Packer’s judgment day is not today.”

Weintraub also spoke to the jury for 30 minutes, laying out the gruesome nature of the case and arguing that Sullivan should be sentenced to death because he killed 14-year-old Grace during the commission of five felonies, including rape.

“What’s the worst thing you can think of to do to a child?” he said. “Because, in this case, we’re going to check off all of those boxes.”

He called Grace’s final 24 hours “hell on earth." After Sullivan raped her and left her to die in a hot attic, Grace broke free of the zip ties on her hands and feet, spit out the ball gag in her mouth, and tried to overcome the drugs in her system, Weintraub said. But Sullivan arrived back at the house and choked her to death.

Prosecutors also called witnesses to testify about the investigation into Grace’s disappearance and murder, and about the state in which she was discovered.

Among them was Cody Blakeslee, who found Grace’s remains in the Luzerne County woods on Halloween 2016 while hunting with his father.

Her torso and head looked like a “[seat-back] cushion from a SUV,” Blakeslee said. “No eyes. No nose. Mouth wasn’t there.”

The jury viewed photos of Grace’s remains, which prosecutors said show how Sullivan viewed her as a “disposable child.”

"He was her judge, her jury, and her executioner,” Weintraub said. “He decided, along with Sara Packer, whether she lived or died, and when, and by what means, and he carried out her sentence.”

Weintraub told the jurors that if they sentenced Sullivan to death, he would be killed humanely, with far more respect than he showed Grace.

As of March 1, 142 people were on death row in Pennsylvania. The state has not executed someone since “House of Horrors” murderer Gary Heidnik was killed by lethal injection in 1999.

For Sullivan to receive a death sentence, all 12 jurors must agree. If they can’t, Bucks County Judge Diane E. Gibbons will sentence him to life in prison.

When Sullivan and Packer were arrested in January 2017, Weintraub called the crimes “depraved” and “unspeakable.”

Sullivan told police he had been planning to kill Grace for years. In July 2016, authorities said, the couple put the plan into action.

They drove Grace from a home they rented in Abington to another they rented outside Quakertown. There, Sullivan attacked the girl, punching her and raping her as Packer watched. Drugged, bound, and gagged, Grace was left to die in the attic. When Sullivan and Packer returned the next day, he suffocated her. The couple stored her body in kitty litter until October, when police arrived at the home to follow up on the investigation. Then they cut up Grace’s remains in a bathtub, drove to Luzerne County, and dumped them in the woods.

As authorities ramped up their investigation, Sullivan and Packer attempted to commit suicide that December, but survived after a roommate discovered them. It was then that Sullivan told hospital staff he had killed Grace.