Anaheim police arrested the girl's father, stepmother and two other family members over the weekend.
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A neighbor didn't want to show her face but said she's heard issues at the home.
"Sometimes they would threaten each other, (saying) stuff like, 'I'm going to kill you,' but I never really thought they would hurt a child," she said.
Yulonda Parker, Shalonda Rae Hill, Louis Hill and Delores Parker are all facing felony charges of torture, child abuse and assault with a deadly weapon.
Neighbor Mary Perez said she saw law enforcement at the home.
"When I saw the social services car, I knew there was something wrong because I had a foster home for about 10 years," Perez said.
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Neighbors said they believe other children live at the home, and they've tried to step in during loud arguments.
"Usually they're arguing and the little kids are crying, but our neighbors come and try to calm them down," said the unidentified neighbor. "But they don't like the advice we give them."
The Orange County District Attorney is not commenting on the case.
Two of the suspects have hired private attorneys. ABC7 reached out to both -- one did not respond and the other had no comment.
All four suspects are being held at the Orange County Jail. Each of their bails is set at $1 million.