Update 10.41pm: A California couple accused of imprisoning and torturing their 13 children have pleaded not guilty.
David Turpin, 56, and Louise Turpin, 49, starved their children to the point that their growth was stunted, chaining them to their beds for months at a time and forbidding them from showering more than once a year or using the toilet, a prosecutor said on Thursday.
"The victimisation appeared to intensify over time," Riverside County District Attorney Mike Hestrin said in announcing charges. "What started out as neglect became severe, pervasive, prolonged child abuse."
The couple were charged with torture, child abuse, dependent adult abuse and false imprisonment. David Turpin was also charged with performing a lewd act on a child under the age of 14.
The litany of abuses was enough to invoke a house of horrors that apparently went unnoticed for years in California and Texas until Sunday, when a 17-year-old girl managed to escape and call the police.
The girl and her siblings had plotted the escape for two years, Mr Hestrin said. Another girl who escaped out a window with the teen turned back out of fear.
Mr Hestrin did not say what finally triggered the girl to act.
When officers arrived at the house on Sunday in Perris, about 60 miles southeast of Los Angeles, they were shocked by what they found.
The children's malnutrition was so severe that it was consistent with muscle wasting and had led to cognitive impairment and nerve damage, Mr Hestrin said. The oldest child, a 29-year-old woman, weighed 82 pounds.
Some of the 13 children had been isolated so long they did not know what a police officer was.
The victims range in age from two to 29. The torture and false imprisonment charges do not include the two-year-old.
The charges date to 2010, when the couple moved to Riverside County from outside Fort Worth, Texas, where the abuse began, Mr Hestrin said.
The parents have been jailed on 9 million US dollars bail each. They pleaded not guilty on Thursday at their first court appearance. If convicted of all charges, they could be sentenced to life in prison.
David Turpin's father, James, the grandfather to the children, said from his home in Princeton, West Virginia, that he did not believe the reports about the abuse.
"I'm going to talk with the children, find out the real story on this as soon as I can get a call through to them," James Turpin told The Associated Press.
The abuse began with the children being tied to beds with ropes and then hog-tied, Mr Hestrin said. When one child was able to wriggle free, the couple began restraining them with chains and padlocks - for up to weeks or months at a time, Mr Hestrin said.
On Sunday, three children had been shackled to beds, though the parents freed two of them when officers knocked on the door, Mr Hestrin said. Officers found a 22-year-old still chained to a bed.
Evidence of human waste on the floor indicated the children were prevented from using the toilet. Sheriff's deputies said the stench in the house was overwhelming.
The children were also beaten and choked, Mr Hestrin said.
The couple may have been able to hide the abuse by schooling their kids at home and functioning in the dark of night. The children were reared on the graveyard shift, with the family staying up all night and going to sleep at 4am, Mr Hestrin said.
While the children were deprived of food, the parents ate well and even taunted the children by letting them see apple and pumpkin pies they weren't allowed to have, Mr Hestrin said.
Similarly, the children were not allowed to play with toys, though they were found throughout the house - in their original packaging.
One of the only things the children were allowed to do was to write in their journals.
Hundreds of journals were found in the home. Mr Hestrin said prosecutors expect the children's writing to provide powerful evidence against the parents.
Earlier: The parents of 13 siblings who were allegedly held in captivity in their family's Southern California home were charged on Thursday with committing years of torture and abuse that left their children malnourished, undersized and with cognitive impairments.
"Severe, emotional, physical abuse," Riverside County District Attorney Mike Hestrin said in announcing numerous charges against David Allen Turpin, 57, and Louise Anna Turpin, 49. "This is depraved conduct."
Prosecutors filed 12 counts of torture, seven counts of dependent adult abuse, six counts of child abuse and 12 counts of false imprisonment against the couple. David Turpin was additionally charged with one count of a lewd act on a child under age 14.
The victims range in age from two to 29. The charges involve acts in Riverside County dating to 2010.
The torture and false imprisonment charges do not include the two-year-old, Mr Hestrin said.
The district attorney said the couple chained their children as punishment.
A 17-year-old daughter who climbed out a window on Sunday and called 911 on a mobile phone had plotted her escape for two years, he said. Another sibling escaped with her but turned back out of fear.
Mr Hestrin said all 13 victims were severely malnourished and as a result some have cognitive impairment and a lack of basic knowledge. He said a 29-year-old female victim weighed 82lb.
The victims were not allowed to shower more than once a year, he said.
In an interview, grandparents of the children said their son's family looked happy and healthy when they last visited California six years ago.
"They were just like any ordinary family," said Betty Turpin, the 81-year-old mother of David Turpin. "And they had such good relationships. I'm not just saying this stuff. These kids, we were amazed. They were 'sweetie' this and 'sweetie' that to each other."
Betty Turpin and her husband, James Turpin, of Princeton, West Virginia visited her son's family for five days at their previous home in Murrieta, California.
Betty Turpin told the Southern California News Group on Wednesday that they were still in shock from learning that her son and his wife were arrested.
Betty Turpin said her son told her he had so many kids because God wanted him to. She said her son shared her Pentecostal Christian faith but he wasn't affiliated with a church in California.
"I feel they were model Christians," she said. "It's hard to believe all of this. Over the years, the Lord knows what happened."
James Turpin said during their visit, "they all looked to me well-adjusted. They weren't skinny or nothing. They were joyous to see us".
He said they were dealing with social workers in attempting to connect with their grandchildren, who are hospitalised as they recover from their ordeal.
On Wednesday, authorities searched the couple's current home in Perris, 60 miles southeast of Los Angeles. Investigators removed dozens of boxes, what appeared to be two safes and pieces of a bed frame.
Some siblings were shackled to furniture in the foul-smelling four-bedroom home that looked perfectly normal from the outside.
The Turpins have lived in two Riverside County communities since moving to California, and police said they were never called to either home, nor were any reports fielded by child protective services.