-- Prosecutors revealed grisly details in a press conference Thursday about the 13 captive siblings case out of California.
-- The brothers and sisters were subject to repeated beatings, including strangulation, and were punished by being chained up, often for weeks or months at a time, prosecutors said.
-- The victims weren't released from their chains even to go to the bathroom and were only allowed to shower once a year, according to prosecutors.
-- The children were rescued Sunday after a 17-year-old escaped and alerted authorities to what was happening.
-- Prosecutors said the teen plotted the escape for more than two years.
The California parents accused of holding their children captive allegedly forced them to shower only once a year, never took them to a dentist, and strangled and beat them routinely, prosecutors said Thursday.
David Turpin, 57, and Louise Turpin, 49, were arrested on charges of torture and child endangerment after their children were found Sunday at their home. The Riverside County Sheriff's Office described the residence as "dark and foul-smelling."
The Turpins both entered not guilty pleas on all counts Thursday. Their next court date was set for Feb. 23.
The children were rescued Sunday after one of the children -- a 17-year-old girl -- allegedly escaped through a window and called 911. Responding officers said the teen was slightly emaciated and "appeared to be only 10 years old."
"It took great courage for her to do that after all those years, and that's all she knows," Riverside County District Attorney Mike Hestrin said of the escape in an interview with ABC News. "She obviously has the personality that she's going to risk herself for others and she did that and she managed to get out. And we're very glad that she did. I don't know how long this would have continued and I don't know what the end result would have been."
Hestrin called the teen the "bright spot" in the tragic story.
"To think she mustered the courage under those circumstances," he said, "maybe it is a testament to the human will and the will to survive."
Hestrin said of the case, "It feels like a bottomless pit. We don’t know where the bottom is."
"You’ve got parents that are torturing their children causing them pain causing them suffering over a prolonged period of time through malnourishment, through physical abuse, through psychological abuse. ... It's horrific," he said. "It's hard to believe that it happens in today’s society, but it does."
The "depraved" details were shared in a press conference led by Hestrin on Thursday.
The abuse intensified when the family moved from Texas to California, Hestrin said. The victims reported that the punishments started many years ago with their parents tying them up, first with ropes. When one victim was able to escape the ropes, "these defendants eventually began using chains and padlocks," Hestrin said.
The punishments lasted weeks or months at a time, he said.
The victims weren't released from their chains even to go to the bathroom, Hestrin said. They were also not allowed to shower more than once a year, he said.
If the children washed their hands above the wrist, they were accused of playing in the water and were chained up, Hestrin said. None have ever seen a dentist and they haven't been to a doctor in over four years, he added.
Hestrin said the parents would buy food including pies and "leave it on the counter, let the children look at it, but not eat the food."
"Supposedly homeschooled, the children lacked even basic knowledge of life. Many of the children didn’t know what a police officer was," Hestrin said. When a 17-year-old was "asked if there was medication or pills in the home, [the teen] didn’t know what medication or pills were."
The parents alleged "sadistic" treatment toward their children was an element of control, he said.
Hestrin added, "The only thing the children were allowed to do in their room or chained up was to write in journals, we now have recovered those journals -- hundreds of them. And we are combing through them."
Hestrin said in an interview with ABC News he thinks the journals will hold "powerful evidence about what was happening from the perspective of the victims."
Hestrin said that at least one of the older victims attended some outside classes. "Louise Turpin would accompany him, wait outside the classroom for him. When he was finished with class, she would take him home," Hestrin said.
The children were not allowed to have toys, although many toys were found in the house in their original packaging, never opened, Hestrin said.
The family would "sleep all day" and be "up all night," typically going to sleep around 4 or 5 a.m., he said.
Authorities gathered the details of the case using physical evidence and interviews, Hestrin told ABC News in an interview Thursday evening.
"This is the beginning," Hestrin said. "We have a lot of evidence to go through, journals to go through, more interviews to do."
The journal will be "significant evidence" in the case, Hestrin said.
"My guess is it's going to be powerful evidence from the perspective of the victims of what was happening in the house," he said.
Hestrin said the 17-year-old worked on a plan to escape for more than two years with her siblings. He said another sibling escaped with her, but that sibling became afraid and returned to the house. He described her escape as a "testament of human will and the will to survive."
When authorities arrived, three victims were discovered chained up, Hestrin said, adding that the Turpins managed to get two victims unchained before deputies entered. He said a 22-year-old old remained chained to the bed when officials came inside.
All the victims except for the toddler are severely malnourished, Hestrin said, adding that the eldest victim -- a 29-year-old woman -- weighs only 82 pounds. He said another child, a 12-year-old, is the weight of an average 7-year-old.
The victims have since been hospitalized for treatment. Doctors told ABC News the siblings were starved for years.
Hestrin added that prosecutors believe all the children were born at hospitals.
Child Protective Services said it is receiving calls from around the world from people who want to help the siblings financially. Because the agency does not want the siblings to be taxed for the money they receive, it is setting up a fund for them to go through the Riverside County Regional Medical Center Foundation. All GoFundMe campaigns that claim they benefit the siblings are fake, CPS said.
The agency also listed the clothes that are needed for the adult patients, which are almost all in children's sizes, a graphic released by Corona Chamber of Commerce showed.
The Turpins have each been charged with 12 counts of torture, 12 counts of false imprisonment, seven counts of abuse of a dependent adult and six counts of child abuse. David Turpin was also charged with one count of a lewd act on a child under the age of 14 by force, fear or duress. They have pleaded not guilty.
Hestrin said that, to him, the torture charges are the most "horrific."
"Causing them pain, causing them suffering over a long period of time," he said.
A lawyer for David Turpin told ABC News, "What we would like the public to know is that our clients are presumed to be innocent and that’s a very important presumption." He added, "We’re going to provide a vigorous defense."
If convicted, they each face a potential sentence of about 94 years to life in prison.
ABC News' Julia Jacobo and Matt Gutman contributed to this report.