A 17-year-old girl who escaped from a Southern California home dubbed a "house of horrors" by authorities told 911 operators that two of her sisters were "chained up."

"They will wake up at night and they will start crying and they wanted me to call somebody," the girl, one of 13 children, said in the January phone call. "I wanted to call y'all so y'all can help my sisters."

A recording of the call was played at a hearing in Riverside County Superior Court that would determine whether the children's parents, David and Louise Turpin, would be tried on multiple child abuse charges. The couple have pleaded not guilty to torture, child abuse and other charges. They are being held on $12 million bail each.

The teen's phone call led officers to the Turpin home in Riverside, where they freed two children and arrested the parents. Investigators described a home smelling of human waste, while the children showed obvious evidence of starvation -- the oldest sibling weighed just 82 pounds.

Prosecutors have claimed the children were locked up as punishment, denied food and toys and allowed to do little except write in journals, which served as an outlet for expression and were seized from the home by authorities.

After their parents' arrest, the children, who ranged in age from 2 to 29, were hospitalized and eventually were released.

Their current whereabouts are unknown. A spokeswoman for the county's social services department declined to discuss the case.

Jack Osborn, an attorney appointed to represent the seven adult children, said earlier this year they were "doing well." They have participated in music therapy programs, made crafts and world-famous cellist Yo-Yo Ma held a special concert for them. They communicated with their younger siblings over Skype.

"They're happy, they are wanting to move forward, they do not want to dwell on the past," he told the Riverside Press-Enterprise newspaper in February. "They want their identity to be now and going forward the things they hope to do, the dreams they have. They do not want people to think of them only as a possible victim, but as young adults setting off on their lives."

Prosecutors planned to have sheriff's deputies testify at Wednesday's hearing, but none of the children was expected to take the stand.

David Turpin's attorney, David Macher, said he was "looking forward to the hearing," but declined to comment further. Louise Turpin's lawyer did not immediately respond to request for comment.

The Associated Press contributed to this report.