Barbour had been scheduled to pick up his three children - Marcus, 5, Nacasha, 4, and Colby, 2 - at the home where they lived with their mother, Christine Pittman, said William Barbour Sr., the victim's father.
Pittman and Barbour never married and had ended their relationship last year, Barbour's father said.
The elder Barbour said his son had visitation rights on Sundays.
He said the children apparently were not at home at the time of the shooting. Pittman's neighbors said the children were staying with their grandmother.
Barbour, a native of Chambersburg and a graduate of Chambersburg Senior High School, had worked at Hennessy Products Inc. in Chambersburg, his father said.
Barbour and Pittman had lived together for about five or six years in Chambersburg and then moved to the Magnolia Court home about two years ago, the elder Barbour said.
He said Pittman "put him out" of the Magnolia Court house several months ago and that his son had been living with his sister and in a shelter in Chambersburg since then.
"His mother and I didn't interfere," Barbour said.
The victim's father said his son had visited him and his wife, Delores, at their Chambersburg home Saturday night.
Most of Pittman's neighbors in the new housing development said they woke up to see the road blocked with police cars and an ambulance.
Police cordoned off the property, including the home with brick and tan siding and green shutters and a large fenced-in back yard, with yellow police tape.
"I think we're in a neighborhood of disbelief," said one man who refused to be identified.
Several other neighbors said they didn't know the family well but have seen police at the home in the past.