The couple's children, who are aged between two and 29 and had all been home schooled, have been treated in hospital since being freed.
The children would stay awake all night until going to sleep at four or five in the morning and slept during the day.
On Wednesday afternoon, several investigators, some wearing black gloves, went in and out of the house, frequently carrying boxes and bags of material they placed in waiting vehicles.
The siblings showered once a year and were chained to their beds for weeks at a time, said Riverside County District Attorney Mike Hestrin. "Some deal with human depravity, and that's what we're dealing with here".
David and Louise Turpin are both from Princeton, West Virginia, relatives say. As of Tuesday, the Riverside County Department of Public Social Services is seeking court authorization to oversee and provide care for the children "to the extent that's necessary, " spokeswoman Susan von Zabern said.
Neighbor Kimberly Milligan said one of those rare encounters occurred in 2015 and especially stood out. One of the adult children attended school but Louise would wait outside his classroom to take him home after the classes. "They immediately shut down".
The girl told cops she was terrified her mum and dad would kill her if she got caught.
The two-year-old was of normal weight but the other children were severely malnourished.
The abuse and neglect started decades ago, when the family lived in Fort Worth, and continued as they moved to Murrieta in 2010 and then to Perris in 2014, Hestrin said in announcing multiple felony charges against the couple.
"This is severe emotional and physical abuse", Hestrin said Thursday.
They were allegedly punished when they washed their hands above their wrists, and beaten regularly, according to the prosecutor.
On Sunday, three children had been shackled to beds, though the parents freed two of them when officers knocked on the door, Hestrin said. "They weren't allowed to have friends over - the normal things that kids do", the children's aunt, Teresa Robinette, told NBC's "Today" show.
The parents would buy food, including apple pies and pumpkin pies, and would put them on the counter for the children to see but would not let them eat any. Circumstantial evidence suggested that such treatment could go on for days, with the children not even been unchained to go to the toilet. Another child initially joined her, but turned back.
"The 17-year-old victim that escaped had been working on a plan with the siblings to escape this abuse for more than two years", he added. He said a 22-year-old old remained chained to the bed when officials came inside. Prosecutors filed charges of torture, child abuse, dependent adult abuse and false imprisonment.
Mr Hestrin said there had been no torture charge filed in relation to the two-year-old because the toddler appeared to be "getting enough food".
Officers raided the house in the small city of Perris, about 70 miles (113 km) east of Los Angeles, on Sunday after the 17-year-old, whose name was not released, called the 911 emergency number on a cellphone. The torture and false imprisonment charges do not include the 2-year-old, who was not malnourished.
The father, David Turpin, 57, is also accused of sexually abusing one of his young daughters.
A judge set bail at $12 million each for the Turpins, who were scheduled to return to court on February 23.
If convicted as charged, they face up to 94 years to life in prison, according to the Riverside County District Attorney's Office. Defence attorneys face a battle to prevent global revulsion against David and Louise Turpin from prejudicing their court case.