Her mother was the great-great granddaughter of James E. Scripps, who founded The Detroit News and built the Evening News Association, which was sold to the Gannett Co. in 1985. His brother E.W. Scripps founded Cincinnati-based E.W. Scripps Co., which owns newspapers, television stations and the Scripps Howard News Service.
At the time of the murder Petrillo was just 22. Her 3-year-old sister Victoria was in the house as her stepfather beat her 47-year-old mother into the coma that six days later killer her.
"In tearful confusion, [Victoria] said daddy was giving mommy many 'bad boo boos,' according to Pirro, a lifelong advocate for abused women. "'Daddy painted mommy red, why make mommy a monster?'"
Before her death, Petrillo's mother had gone to Westchester Family Court to get an order of protection against her husband, but was turned away because the judge was on vacation.
Scott Douglas's body was found three months later downstream in the Bronx, she said. "The irony was his watch had stopped at exactly midnight on New Year's Eve."
"The whole thing is horrific and the irony is stunning," said Pirro. "It's the cycle of violence and continuing tragedy and the ripple effect. Long after everybody stopped talking about it, it was never over in the family," she said.
Later, Petrillo and her older sister were devastated by losing a bid to take custody of Victoria. Petrillo was further traumatized when they lost a lawsuit, charging the state failed to protect their mother.
"Virtually everyone who develops this kind of grief has a close relationship with the person who died," said Shear.
When grief lasts six months beyond a death, psychiatrists consider complicated grief, which has been linked to higher incidences of drinking, cancer and suicide attempts.
In depression, a person is "sad and uninterested in everything," according to Shear. "They don't yearn and long for things -- they don't care."
In post-traumatic stress syndrome, which might well have played a role in Petrillo's sadness, "You are focused on the event, as opposed to the person," she said.
But in complicated grief, patients "relive it over and over and cannot stop," said Shear. "It's not going anywhere. That's where you get the constellation of symptoms and it's the center of the intense longing for the person. At the same time, they are avoiding the painful parts."
Normal grief, being preoccupied with thinking how much the person will be missed, is processed over time.
"You start to think, I can manage, I don't know how but I will. And gradually over time, you are really rehearsing for the fact that the person is not there," she said.
Ultimately, the bereaved learns the loved one is gone.
"Petrillo might think of her stepfather and how could he could have done this and it never should have happened, instead of understanding she [her mother] is gone and I have to make the best of it," Shear said. "It becomes the focus of attention, rather than the death itself."
"The mind takes over and starts imagining how it didn't have to happen, instead of how it happened," she said.
Shear has developed cognitive behavioral therapy that requires the patient to relive the death, talking about it in detail on tape and replaying it at home.
In a 2005 study in The Journal of the American Medical Association, Shear presented evidence that this treatment is twice as effective as traditional therapy.