Grace Packer parents

Man who admitted raping and murdering young teen was ‘substantially dominated’ by victim’s adoptive mom, psychologist says

A man potentially facing the death penalty for raping and murdering a 14-year-old girl was acting in service of his girlfriend, the victim’s adoptive mother, a psychologist argued in court this week.

As CrimeOnline previously reported, a witness testified this week that she heard Jacob Sullivan say he “liked” murdering Grace Packer in 2016. Prosecutors argue the brutal attack was planned by the teen’s mother, Sara Packer, in an effort to live out a sexual fantasy.

According to testimony by Dr. Frank Dattilio, Sara Packer held significant sway over Sullivan, who pleaded guilty to related charges — including murder and child rape — earlier this month.

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Sullivan confessed to conspiring with Sara Packer to rape her adopted daughter as she watched. They then forced her to overdose on sleep medication before tying her up and leaving her in a hot attic.

He said he strangled the girl after returning to the location and finding she was still alive. Hunters found Grace Packer’s remains discarded in Luzerne County weeks later.

RELATED: Killer mom says she planned to keep daughter Grace Packer alive as sex slave ‘for years’ so boyfriend could rape her anytime he wanted

The psychologist contended that Sullivan was eager to please his girlfriend and was “substantially dominated” by her, according to the Morning Call.

“The worst was brought out of him, I believe, by this relationship,” he said from the witness stand. “It became a slippery slope.”

He went on to describe Sullivan as the victim of child sexual abuse who, as an adult, wanted to live as a polygamist.

Prosecutors sought to poke holes in that narrative, however, including a line of questioning from Bucks County District Attorney Matt Weintraub that resulted in Dattilio’s admission that he did not know for certain whether the highly intelligent Sullivan had simply fabricated a more sympathetic story.

Nevertheless, the psychologist portrayed Sara Packer as manipulative and “very smooth in her way of dealing” with Sullivan.

“If she threw out a fantasy, he would do whatever he could to follow it,” Dattilio said.

When Sara Packer addressed the jury, however, she said that she was the one “wrapped up in Jake’s fantasy,” claiming she “didn’t think [she] could tell him no without losing him.”

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