(CNN) For years, the 13 starving children lived in squalor, shackled with padlocks while their parents taunted them with pies left on the counter of their California home, authorities say.

David and Louise Turpin lived with their children between ages 2 and 29 in Perris, southeast of Los Angeles.

What started as neglect escalated into years of horrific torture, authorities said, with the parents allegedly depriving the children of water and feeding them small portions of food on a strict schedule.

They'd sleep during the day and stay awake at night, sometimes chained to their beds and not allowed to use the restroom, according to authorities.

After years of alleged abuse, one teenage girl escaped Sunday and called 911. Investigators went to the house and freed the children, prompting days of investigations that led to a series of charges Thursday.

"As a prosecutor, there are some cases that haunt you," Riverside County district attorney Mike Hestrin said Thursday. "Some deal with human depravity, and that's what we're dealing with here."

Here's what we know:

The family

David and Louise Turpin, along with their 13 children.

David and Louise Turpin are both from Princeton, West Virginia, relatives say. Of their 13 children seized from the home, six are minors.

The reclusive family has lived in their suburban Perris neighborhood since 2014, but neighbors said they didn't see them much.

Neighbor Kimberly Milligan said one of those rare encounters occurred in 2015 and especially stood out.

Milligan said she was checking out Christmas decorations on nearby homes when she saw the older Turpin children putting up a Nativity scene outside their house and complimented their decorations.

Turpin wedding video screengrab.

"They just froze," Milligan recalled. "They immediately shut down. You could tell they were terrified."

The children were thin and appeared malnourished, Milligan said.

Before the Turpins moved to Southern California, they lived in Texas, where a former neighbor said they kept to themselves.

The alleged torture

The siblings showered once a year and were chained to their beds for weeks at a time, Hestrin said.

They were allegedly punished when they washed their hands above their wrists, and beaten regularly, according to the prosecutor. The parents would buy toys, the prosecutor said, but keep them in the packaging. They were allowed one meal a day and one shower a year, Hestrin said.

"Circumstantial evidence in the house suggests that the victims were often not released from their chains to go to the bathroom," he said.

The escape

Before police arrived to set them free, one teenage daughter made a dash for freedom Sunday by crawling out of a window at the home and calling 911 using a deactivated phone, authorities said. Another sibling came with her, but got scared and returned home.

It was a plan the 17-year-old and her siblings had planned for two years, according to Hestrin.

When police arrived, some of the children were still shackled to their beds, but the parents had unchained two, Hestrin said. Some of the victims' growth was so stunted, they looked younger than their ages, according to officials.

"If you can imagine being 17 years old and appearing to be a 10-year-old, being chained to a bed, being malnourished and injuries associated with that, I would call that torture," Riverside County Sheriff's Capt. Greg Fellows said.

One of the victims is age 12 and is the weight of a 7-year-old while the 29-year-old was 82 pounds, Hestrin said.

When authorities went to the house, the mother appeared "perplexed" on why they were there, according to Fellows.

The investigation

David (far right) and Louise Turpin look on Thursday with attorney Jeff Moore during the Turpins' arraignment.

David Turpin, 56, and Louise Turpin, 49, were charged with 12 counts of torture.

"We are not charging torture on the 2-year-old," Hestrin said. "The 2-year-old ... was getting enough to eat. The basis of torture charge is not just one thing, it's severe abuse over time."

Other charges include seven counts of abuse of a dependent adult, six counts of child abuse or neglect and 12 counts of false imprisonment. David Turpin was also charged with a lewd act on a child by force or fear of duress, Hestrin said.

The Turpins pleaded not guilty on all counts and a judge set bail at $12 million for each defendant. Their next court date is February 23.

If convicted of all charges, they face a maximum sentence of between 94 years and life in prison.

"What we would like the public to know is that our clients are presumed to be innocent, and that's a very important presumption," said David Macher, a public defender for David Turpin.

What next?

As the criminal case proceeds, the future of the children will likely be decided in another courtroom.

"When there are serious allegations of child endangerment, most likely child protective services will recommend a fast track to adoption," said Amy Heilman, director of foster care and adoption at the Children's Bureau in Los Angeles.

"However, there are times where the court may not want to make that ruling until it's further on in the criminal case."

The process to terminate parental rights is determined in dependency court, and birth parents have the right to contest the termination, she said.

In the short term, the children will be placed in foster care, she said. Foster care parents can opt to become the adoptive parents.

Meanwhile, the children are being cared for at local hospital, and face a long road of mental and physical treatment.

As a result of the alleged mistreatment and trauma over a long period of time, they could suffer from complex post-traumatic stress disorder, said psychiatrist Dr. Frank Ochberg

"We can assume that there could be depression and nightmares," Ochberg said.

He was optimistic about the possibility of recovery down the road.

"While there can be a number of complicated and interrelated medical, social and psychological disorders, there have been amazing and heartwarming examples of people who are survivors," Ochberg said.