Her husband, Edward Todd II, 51, then shot himself, Hughes said. The coroner ruled the death a suicide by a gunshot wound to the head, Hughes said.
The daughter, Brittany Todd, called 911 as she ran with her about 2-year-old son, Joseph, to her car and drove away, police and a neighbor said.
"The call said that the father had shot the mother in the head and was in the house and was intoxicated," Hughes said. The daughter heard only two shots, he said.
On Nov. 20, 2010, Edward Todd threatened to kill his wife if she sought a divorce, according to a complaint she filed three weeks later.
Mary Todd told police her husband had ripped off her clothes, pointed a semiautomatic gun at her head, and threatened to kill her, according to the affidavit of probable cause.
He also "pointed the firearm at himself and threatened to commit suicide in front of her so that she would have to suffer living with the guilt," according to the affidavit.
Brittany Todd returned home to find her mother taking the gun from her father, according to the affidavit.
Edward Todd was charged with simple assault, making terroristic threats, recklessly endangering another person, and harassment. But at his preliminary hearing on Jan. 11, 2011, Mary Todd recanted her statement and the charges were dismissed, said Robert James, Bucks County deputy district attorney.
Hughes said he could not say whether the gun allegedly used in the 2010 incident was the one used Thursday. And he could not say whether that gun or the "multiple" weapons in the house were registered.
Police removed only the handgun that had been fired, he said. "There was no need to take the [other] guns out of the house."
Harry Bose, who lives across the street from the Todd house, said he had talked to the husband that afternoon, and "everything seemed normal."
"He had just sold his mother's house, cleaned it out, and was unloading his truck," Bose said.
Edward Todd did remodeling and construction work, while his wife was a "stay-at-home mom," Bose said. He owned two motorcycles, and the couple would take evening rides on one of them, Bose said.
"It seemed like they were getting along," he said. "It was a shock to me."
The couple's son, Edward III, who did not live in the house, also was shocked, Bose said. "He kept saying he couldn't believe his father did that," the neighbor said.
Another neighbor, Paula Dean, said the Todds, who have lived on the quiet block for about 25 years, "were a very nice family until about five years ago."
They used to keep the house and yard nice, said Dean's daughter, Janet Morelli, who lives behind the Todds' house, "and then they just let everything go."
"We kept wondering what happened," she said.
Their son graduated from high school and moved out about that time, "and that's when it happened," Morelli said.
In their neighborhood, "we watch out for each other," Bose said.
"You see it [shootings] on TV all the time," he said, "but you never expect to see it on your own block."
Contact staff writer Bill Reed at 215-801-2964, firstname.lastname@example.org, or follow @breedbucks on Twitter. Read his blog, "BucksInq," at www.philly.com/bucksinq.