Transcript for 13 siblings allegedly held captive at home by parents: Part 1
Reporter: Perris, California, a sleepy little town of 68,000 souls nestled in Riverside county, about halfway between L.A. And San Diego. How are you feeling? Feeling good. Ready to do this? Reporter: Its biggest claim to fame is the sky diving center at the city airport that's become a Mecca for sky divers across the country. Most of the time we go to Perris for skydiving stories. It's world famous. Reporter: But this week, Perris hit the national news for a much different reason. What some are calling a house of horrors discovered in a California suburb. Reporter: It all started on Sunday in Muir wood road in this neighborhood of tidy study stucco houses and manicured lawns. Here at this unassuming four bedroom home, just before 6:00 in the morning, police say two siblings slip out of a window. One gets scared and bolts back inside. But the other child, a 17-year-old girl, makes her way down the sidewalk away from the house and then pulls out a deactivated cell phone and dials 911. And she explained that her and her siblings were being held against their will. And some of them were chained. Also showed some photos that led the deputies to believe that the information she was providing was accurate. Reporter: Deputies swarm the neighborhood and the house, and behind that neat exterior, they find an interior world that they describe as surreal and sadistic. Deputies, when they arrived inside the house, they noticed that the children were malnourished, it was very dirty and the conditions were horrific. Inside a family home in southern California. Tortured by their own parents. Reporter: As the news breaks, reports of what those walls hid shocked the country. Photos from the family Facebook page show the 13 siblings who were alleged to be living in dungeon-like conditions, living in squalor. My jaw dropped farther to the floor. Thirteen children. Held captive. It's just unbelievable. Reporter: Their parents, who were arrested at the scene, were alleged to have even shackled their own children to furniture. These defendants eventually began using chains and padlocks to chain up the victims to their beds. The defendants were able to get two of the victims unchained before the police actually entered. Reporter: The children range in age from two to 29. Seven of them are actually adults, but look much younger because of severe malnourishment. To give you an example, one of the children at age 12 is the weight of an average 7-year-old. The 29-year-old female victim weighs 82 pounds. 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. Reporter: These are the accused parents. 56-year-old David turpin and his wife, 49-year-old Louise turpin. We would ask the court to waive reading. Reporter: In court yesterday the turpins pleaded not guilty to a combined 75 counts including charges of torture, child abuse, neglect and false imprisonment. The couple is being held on $12 million bail each. Mr. Turpin, I've discussed with you that you have a right to a speedy preliminary hearing. Reporter: For authorities, the biggest mystery, how the turpins got away with the alleged abuse for so many years, hiding in plain sight, taking their kids on what seemed all American vacations. I can't explain why these parents did these horrible things. Reporter: The story of the turpin family begins far from the desert and palm trees of south California, 2,300 miles away to be exact, in the green hills of West Virginia. Here in the heart of appalachia sits the small town of princeton, population 6,400. We're pretty much a rural untain area. Coal and of course, you know, railroads. Reporter: Louise turpin, born Louise Robinette, grew up in this modest princeton house, the daughter of an official at the county courthouse. We had a pretty Normal life inside the home that I lived in. Reporter: Her younger sister Elizabeth says that Louise was a strong-minded, willful kid. It was her way or no way. And if she had to sneak around to do it, she would do it. Reporter: The younger sister says she and others in the family were sexually abused. She wonders whether the impact on the family might have been a contributing factor. There was sexual abuse by a family member, a close family member, and not our parents. We were not allowed to talk about it. And I'm not making excuses for my sister, but I think that that may have been an underlining issue. Reporter: Meanwhile, six miles away on the outskirts of town, David turpin grew up in this red brick house. David went to school at princeton senior high school, shown here in the yearbook. He's sporting the same bowl cut haircut he has today. Among his activities listed, the bible, science and chess clubs. He was quiet, nerdy. He was a good student. He tended to dress well. David wasn't known to go out and party with the other kids or anything like that. Described as something of a home body. Reporter: David and Louise's families attended the same west Virginia church. I've known David all my life. My parents and his parents were pretty close. We all attended princeton church of god for years and years and years. Reporter: The family friendship between David and Louise turns to love. They start dating when he's 22-years old and she's just 15. But in the first sign that there might be something off about this couple, just a year into their romance, they decide to run away from their families to Fort Worth, Texas. It took the police three days to find her. And she was only 16. He was almost 23. My mom wanted to press charges, and my dad had mixed emotions about it. Because we were taught that you don't have sex outside of marriage. Reporter: So with Louise just 16 years old, the two lovebirds tie the knot in 1985. They had a small church wedding. Only close family members came. But Louise and David were really happy. And I remember them just saying they just wanted to get on with their life. Reporter: And just a year later they did just that, leaving West Virginia in their tracks for good and moving back to Fort Worth. She told me one time that she didn't want to keep up with the family because of her past. It reminded her of it. And she just wanted to leave it all behind and start over.
This transcript has been automatically generated and may not be 100% accurate.