RIVERSIDE, Calif. -- A judge on Thursday ordered a California couple to face trial on torture and child abuse charges after prosecutors presented evidence their children were subjected to years of filth, starvation and cruelty that included beatings with a wooden paddle and caging them as punishment. Riverside County Superior Court Judge Bernard Schwartz found probable cause that David and Louise Turpin abused 12 of their 13 children for years.

Investigators testified that the couple chained their children to beds and deprived them of food. The judge threw out a child endangerment charge involving the youngest daughter.

Doctors who examined the children ranging from 2 to 29 found signs of severe malnutrition and muscle wasting. Some struggled to speak and a 12-year-old girl didn't know the full alphabet.

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As the Turpin parents appeared for a second day at a preliminary hearing, their seven adult children were in an adjacent courthouse for a closed-door guardianship proceeding.

Jack Osborn, a lawyer for the adult children, said no decision was reached on appointing the Riverside County as their long-term guardian. Bailiffs cleared the hallway after the appearance for the privacy of the children who could be seen from a distance in silhouette as they were ushered out of view.

Horrific testimony of starvation, squalor and brutality was presented Wednesday. Photos showed two pale, malnourished girls shackled to bunk beds. Their sister, who surreptitiously snapped the photos, was heard pleading in a 911 call for someone to come and save her siblings.

In the call played in court, according to CBS Los Angeles reporter Nicole Comstock, the girl said she doesn't know much about her mother and that the woman "doesn't take care of us….they only chain us up if we do something wrong."

The girl said the house had so much dust she couldn't breathe, and that she hadn't taken a bath in more than a year, Comstock reported. She told the dispatcher she broke out of the home to help her siblings because she couldn't stand to hear and see them crying anymore, the station reports.

"They will wake up at night and they will start crying and they wanted me to call somebody," the 17-year-old told the dispatcher in a quivering, childlike voice.

David and Louise Turpin have pleaded not guilty to torture, child abuse and other charges. Each is being held on $12 million bail and could face up to life in prison if convicted. They are scheduled to return to court Aug. 3.

The couple was arrested in January after their 17-year-old daughter, who spent two years planning an escape, climbed out a window and placed the 911 call. By the time police arrived at the Perris house 70 miles southeast of Los Angeles, two girls, 11 and 14, had been hastily released from their chains, but a 22-year-old son remained shackled.

Louise and David Turpin at a preliminary hearing June 20, 2018 in Riverside County Superior Court CBS LA reporter Nicole Comstock via Twitter

The young man said he and his siblings had been suspected of stealing food and being disrespectful, Riverside County sheriff's Detective Thomas Salisbury said. The man said he had been tied up with ropes at first but later, after learning to wriggle free, was restrained with increasingly larger chains on and off over six years.

Photos of the girls' tiny wrists wrapped in heavy chains drew gasps from some court attendees.

Investigators testified that the Turpin children lived mostly in locked rooms and were deprived of food, toys, games, schooling and most outside contact, barring two family visits to Disneyland and Las Vegas. One of the first investigators to speak to the girl testified that she told him her sisters had been chained up because they had stolen candy from the kitchen, CBS Los Angeles reported.

According to the testimony, the 17-year-old girl told authorities her father sexually abused her when she was 12. David Turpin is also facing a charge of a lewd and lascivious act on a child under 14. An investigator also testified the girl told authorities some of her siblings acted as hall monitors so the other siblings wouldn't steal candy or food, and the siblings would eat only once a day, one at a time while standing up.

Sheriff's Deputy Daniel Brown said one daughter told him that she knew her sister had contacted police when she heard a knock at the door and saw flashing lights outside the window.

"She said she was finally going to become free," Brown said.

Senior investigators with the county district attorney's office testified that doctors and medical records showed some adult children were 32 pounds underweight.

The oldest son attended classes at a community college but investigators have said his mother waited outside the classroom and immediately brought him home after classes.

The 11-year-old girl who had been shackled to her bed had stunted growth from malnourishment and her arms were the size of an infant's, investigator Patrick Morris said.

In her 20-minute 911 call, the 17-year-old who escaped told the dispatcher: "We don't really do school. I haven't finished first grade."

The girl told sheriff's Deputy Manuel Campos that she hadn't bathed in a year and that she didn't know the date or the month, he testified.

About two years ago, her mother choked the girl for watching a Justin Bieber video on a cellphone borrowed from her sister, telling her: "You want to die and go to hell," according to Campos.