(CNN) -- Four members of an Arizona family have been charged with murder in the death of a 10-year-old girl whose body was discovered locked in a box outside her family's house. She had suffocated.

The charges were filed Thursday, a day after Phoenix police arrested the four.

Police released a statement saying the four relatives of Ame Deal had been entrusted with caring for her. The arrest came after police said they learned that the family routinely confined her inside the box when she misbehaved.

John and Samantha Allen, both 23, were charged with first-degree murder after confessing they had locked Deal in the box July 12, the statement said.

Cynthia Stoltzmann, 44, and Judith Deal, 62, were charged with child abuse and kidnapping after both admitted they had locked the girl in the box on previous occasions, it added.

CNN was not able to reach Judith Deal's attorney; it was not immediately clear whether the remaining three have retained counsel.

Stoltzmann was the victim's aunt and legal guardian, according to police spokesman Sgt. Trent Crump. Deal's and the Allens' relationship to the girl was not clear.

"When we initially responded to the scene, we filed it as an unknown death," Crump said.

When first questioned, the family members told police that Deal had climbed into the box and suffocated while playing hide-and-seek, police said.

That was the account Stoltzmann gave to CNN affiliate KNXV-TV on July 13, the day after family members reported finding the body.

"I don't break down well in front of other people, but when I'm by myself, I can lose it real easy," Stoltzmann said. "She was an awesome hider, let me tell you. ... There were places she would squeeze into that I didn't think my dog could squeeze into."

But Crump said that, after investigating the incident, police came to believe the girl was killed.

Crump said Thursday that the case has troubled even veteran detectives.

"This child died at the hands of those who were supposed to love and care for her. ... This case has turned the stomachs of some of our most seasoned detectives," he said.

CNN's Chelsea Bailey contributed to this report.