Louise and David Turpin arraignment courtroom drawings

13 captive siblings forced to shower once a year, strangled, subject to frequent beatings: Prosecutor

-- Prosecutors revealed grisly details in a press conference Thursday about the 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.

Courtroom sketch of Louise and David Turpin by Mona Edwards

Courtroom drawing of Louise and David Turpin by Bill Robles

The California parents accused of starving and shackling their 13 children 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."