The couple's two sons - ages 4 and 5 - witnessed the horror, one of them "talking about daddy killing mommy," according to police.
In what evidently was a jealous rage, the father killed his wife inside their Drexel Hill apartment early Thursday, fled with the children, set off a multi-state manhunt, and later took his own life, said Michael J. Chitwood, police superintendent in Upper Darby Township.
Keith Belajonas, 32, fatally shot and stabbed Christina Corrigan Belajonas, 28, shortly after 2 a.m. then drove to Staten Island, N.Y., with the boys, police said.
The incident rocked the tranquil, tree-lined neighborhood of brick homes, in the 200 block of Abbey Terrace, in the middle of the night.
After Pennsylvania State Police issued an Amber Alert at 4:07 a.m. for the abduction of the youngsters, who "absolutely witnessed" their mother's killing, Chitwood said, they were found safely.
Police were able to track Belajonas by "pinging" his cellphone and getting hits in Trenton and Windsor, N.J., according to the New York Daily News.
Police said that about 5:30 a.m. Belajonas stole beer, cigarettes and cash at a local CVS where his brother works, and left the boys there unharmed.
A citizen dialed 911 after recognizing Belajonas' SUV in Staten Island from the Amber Alert. Shortly before 7 a.m. police spotted the car and chased Belajonas's vehicle as it weaved through traffic, before stopping on dead-end residential street, the Daily News said.
Belajonas was found dead moments later in what appeared to be a suicide, police said. A gun was recovered from the Pathfinder, but it wasn't immediately known whether the firearm was legal.
Belajonas had earlier posted an item on Facebook about a quarrel with his wife, claiming she had been unfaithful, according to Chitwood.
Chitwood said that a friend of the couple, who married in June 2011, had sent police the text of a message in which Belajonas wrote that he had a dispute with his wife because she was cheating on him -- and he won.
Christina Belajonas suffered a gunshot wound to the head and was "cut up pretty good," said Chitwood, who said a knife was found near her body.
"I'm shocked this happened here," said Toni Stathis, 33, who lives a few doors away. The street, she said, "is always quiet."
Joe Ryan, who has lived across the street for about 40 years, said that when he was out walking his dog around midnight he saw the couple smoking on the balcony of their second-floor unit. Then, around 2 a.m., he said, he heard a "commotion."
About that time, police responded to the apartment to reports of gunshots. There, police found Chistina Belajonas's body, Chitwood said. The children Christopher, 4, and Robert, 5, were gone.
Upper Darby police said neighbors had heard sounds of a struggle at the residence, and one of the boys was heard to say that his mother was dead as Belajonas and the boys left the apartment.
When found, the children were taken to a hospital for observation as a precaution. They appeared to be in good physical condition, police said.
A relative said Thursday afternoon that Christina Belajonas's father was on his way to New York to pick up the children.
"The case is closed," Chitwood said.
He said that police hadn't been called to the couple's home before and that there were no earlier reports of domestic violence. Keith Belajonas had no criminal record in the Philadelphia region, he said.
The couple has lived on Abbey Terrace only since September 2013, according to property records. Prior to that, the records indicate they lived in Staten Island. Chitwood called the couple's apartment filthy and "unfit for habitation."
"No human being should live the way those kids had to live," he said.
Ryan said that Belajonas and his wife had come across as standoffish. "They didn't seem to want to associate much with neighbors," he said. "They weren't looking for friends. I think they were having problems."
Ryan said Belajonas was not working, and that may have been a source of tension.
He said that the victim appeared to have been an attentive mother who was always with her sons.
"The poor kids," Stathis said. "They they are not going to have a mother and father growing up."
Saul "Tom" Corrigan, 83, Christina Belajonas's grandfather, was up early shaving when "a front lawn full of Upper Darby police" banged on the door of his Folcroft home. They were looking for the victim's father, who lived at the home,to give him the sad news.
Christina Belajonas "grew up here," said Saul Corrigan, adding that her parents had divorced when she was young. "Me and my wife raised her."
Corrigan said his granddaughter graduated from Archbishop Prendergast and attended the New York Institute of Technology for a while before dropping out for financial reasons, he said.
"She was a good kid," he said. She did well in school and had an "average" life studying and hanging out with girl friends.
He said that his granddaughter and her husband moved to Drexel Hill because she didn't like living in New York. "They seemed to get along real good," he said.
Belajonas' MySpace page shows him holding two handguns, arms crossed, and shoulders tattooed.
Saul Corrigan said his granddaughter was a practical nurse and phlebotomist.
Rosanne Graham, the adminstrator at Little Flower Manor, a skilled-nursing facility in Darby Borough where Christina Belajonas worked until a few weeks ago, said she was a "good person" who was devoted to her children. The staff at the facility was having a hard time with the news of her death, she said.
Said Graham, "She was a great co-worker who was respected and loved by her co-workers."
Saul Corrigan said he did not know how his daughter had met Belajonas, but added, "I sure the hell wish she hadn't."