Shortly before 6:15 p.m. Sunday, shots were heard in a blue-collar neighborhood in Oak Cliff, a neighborhood about four miles from downtown Dallas.
"I've talked to some of the neighbors who live out here that heard the shots and they say it sounded like a string of fireworks going off," Dallas police homicide Sgt. Gary Kirkpatrick told CBS station KTVT. "There was repeatedly, one shot after another, a slight pause and then multiple shots again."
A woman, bleeding and screaming, ran from the house. When police arrived, they found bodies in the kitchen and living room of the one-story residence.
A 29-year-old man was arrested and was being questioned in the deaths of his wife, 32; two daughters, 7 and 1; his father-in-law, 56, who was visiting; and a 20-year-old woman.
Names were withheld pending notification of next of kin.
Neighbors said after they heard gunshots, they saw the man speed away in the family's silver-colored sport utility vehicle. The car and suspect were spotted at a shopping center about a block away after police arrived at the residence.
A semiautomatic handgun was recovered at the residence, Kirkpatrick said. Four of the five victims died at the scene; the youngest girl died at a hospital.
Police said it was one of Dallas' most tragic episodes of family violence.
"This is the worst that I've ever seen, and I've been in homicide 10 years," Kirkpatrick said. "There's never been one of this magnitude."
The woman who survived the attack "was shot in the upper body. Serious to critical is all I can say at this time," Kirkpatrick said.
Kathleen Beathard, public relations director for Methodist Hospitals of Dallas, said the gunshot damaged a major artery, and the woman was given 42 units of blood during surgery.
Kirkpatrick said a brother of the suspect told police the family had some domestic problems, but that he didn't believe the wife had reported it to police.
"He said he knew his brother had a gun, but he was surprised this happened. He said to his knowledge his brother had never been in trouble with the police," Kirkpatrick said.
Several people who apparently were relatives of those who were killed arrived several hours after the shooting. Some were crying uncontrollably as they waited in an area that was cordoned off by police.
Neighbor Delia McClendon said she watched in horror as the infant was taken from a stretcher and into an ambulance.
"They are wonderful people," she said. "I thought they were a close family."