(CNN) Chained to their beds for weeks at a time. Showered once a year. Beaten and starved. Officials say life for the Turpin family's 13 children was one of extreme horror and abuse.

"Sometimes in this business we're faced with looking at human depravity," Riverside County District Attorney Mike Hestrin said at a news conference on Thursday. "And that's what we're looking at."

Hestrin revealed the conditions that forced a 17-year-old girl to escape earlier this week through the window of her parents' Perris, California, home, seeking help for herself and her 12 siblings, ranging in age from 2 to 29. She had reportedly been working on her escape plan for more than two years.

Hestrin painted a bleak picture -- what he called "a snapshot" -- of the inside of the Turpin family home, previously described as "dark and foul-smelling."

These are the conditions authorities say they endured.

Punished with chains and padlocks

According to officials, the alleged abuse seems to have intensified over time, starting when the Turpins lived near Fort Worth, Texas.

The Turpin children were often tied up for "weeks or even months at a time," Hestrin told a roomful of reporters on Thursday.

The victims told investigators the practice started as punishment many years ago, Hestrin said. Initially, the children were tied up with ropes, but when one victim, who was hogtied, escaped, the Turpins turned to chains and padlocks, Hestrin said.

To the Turpins, it was "a form of punishment," Hestrin said in the news conference. The children were often left shackled to their beds for "weeks or even months at a time," he said.

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

Police say several of the victims were still chained to the beds when police arrived at the Turpin residence on Sunday, though the parents tried to release them.

Denied showers and medical care

The Turpins allegedly denied their children what most people would view as basic human rights.

The victims were allowed to shower once a year, according to the district attorney. They were apparently allowed to wash their hands, but if they "were found to have washed their hands above the wrist area, they were accused of playing in the water," Hestrin said.

David and Louise Turpin are seen in booking photos released by the Riverside County Sheriff's Department.

This was one of the offenses the Turpins allegedly deemed punishable, and the child would be chained to their bed.

The Turpins, Hestrin said, also fed their children "very little on a schedule." The parents would buy food for themselves, but their kids weren't allowed to eat it. Instead, Hestrin said, "they would buy food, including pies -- apple pies, pumpkin pies -- leave it on the counter, let the children look at it, but not eat the food."

According to the district attorney, only the youngest, a 2-year-old, was getting enough to eat. But the child's siblings, because of the abuse and neglect, are severely malnourished and have cognitive impairment as a result, Hestrin said.

As for health care, none of the children has seen a doctor in more than four years, Hestrin said, and none of them had ever seen a dentist. When questioned by police, the 17-year-old who escaped made it clear she didn't even know what "medication or pills" were.

Kept isolated and starved

If the children weren't chained, then they were locked inside different rooms within the house. There were no toys in those rooms, or stuffed animals, despite the fact that plenty of toys were found inside the house in their original packaging, according to Hestrin.

The only thing the children were allowed to do while inside their rooms was write in journals, hundreds of which have been recovered by authorities, Hestrin said. They will be looked through for evidence in the case against the Turpins.

Apparently nocturnal, the family wouldn't go to sleep until 4 or 5 a.m., Hestrin said, and they would sleep all day.

When asked if this was an attempt by the Turpins to conceal their actions, Hestrin said, "You know, crimes like these happen behind closed doors, in dark rooms, and so of course people who commit these types of crimes have to hide their crimes, and I think that was part of it."

As a result of their isolation, Hestrin said "the children lack a basic knowledge of life." When the police came to rescue them, he said, many of the victims didn't even know what a police officer was.