The five were apparently stabbed to death. A fifth child, a girl, survived and was hospitalized with injuries described as serious, police said.
The woman was detained by police after the bodies were found inside the home in Loganville, Gwinnett County police Cpl. Michele Pihera told reporters at the scene. Police later charged 33-year-old Isabel Martinez with five counts of malice murder, five counts of murder and six counts of aggravated assault.
"She was quickly taken into custody and right now she's at Gwinnett County Police Headquarters being interviewed," Pihera said. Police have not said whether she was injured and said a motive wasn't immediately known.
"Right now we believe we have everybody involved in this crime," Pihera said, adding that she does not want people in the community to think that a dangerous person is at large.
"What her motivations are for committing this horrendous crime, we still don't know," Pihera added.
Pihera said the mother was speaking Spanish in the 911 call, which initially made it difficult for operators to communicate with her. The county sheriff's office said Martinez was being held for US Immigration and Customs Enforcement but didn't provide further details.
Early indications are that a knife was used to attack the five, though a medical examiner will make the final determination about the cause of death, Pihera said.
In Chicago, relatives of the family said Martinez's father died in Mexico one day after Father's Day.
"She was a little down and depressed because of that, but we just didn't think it was so bad. That she was so depressed that she would come to this point," said Maria Salazar, of Chicago, godparent of one of the deceased children.
Salazar's husband, Emiliano Romero, is the cousin of Martinez's now-deceased husband.
The Chicago relatives said the Georgia couple had been married for 10 years, and the slain father was 38. The four children killed included two daughters 10- and 7-years-old and two sons, 4-years-old and almost 2-years old. Salazar and Romero said they are the godparents of the 4-year-old victim. Relatives said the only surviving child was a 9-year-old daughter.
"That child was taken to an area hospital where he or she is in serious condition, but is being treated for these injuries," Pihera said.
Some neighbors in the small, largely Hispanic neighborhood said they had no clue anything was amiss in the home until police mobbed the scene Thursday morning. The neighbors said the Spanish-speaking family had moved to the community recently, and their children seemed happy playing with other neighborhood kids.
"She seemed so good and happy. And she loves her kids. I really don't know what happened," said one neighbor.
"They were really happy on the Fourth of July. They were like any typical family," said another neighbor.
The Chicago relatives expected to see the family soon - for fun, not a funeral.
"They had plans of coming, maybe next week or sometime this month to visit us," Salazar said.
Police initially said in a statement that a woman inside the home called police at 4:47 a.m. Thursday to report a stabbing and officers answering the call found the five bodies inside.
Outside the single-story home with white paneling and black shutters, neighbors sat in their front yards. Crime scene tape surrounded the home and parts of the yard in the Loganville area, about 30 miles (48 kilometers) east of Atlanta.
Victoria Nievs said the children's mother had recently suffered the death of her father.
Jim Hollandsworth is spokesman at The Path Project, a nonprofit organization that runs an after-school program that the family's children participated in. He said the family had been in the community for a few months. While the children spoke English as a second language, he said, they were fluent.
"It's awful. It's devastating. Everyone is in complete shock," he said. "The kids were engaged in what we're doing. They were happy. They were fantastic kids with a bright future."
The Salazar family in Chicago has started a GoFundMe campaign to raise money to pay for their relatives funeral and burial costs.
WLS-TV contributed to this report.
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