The brother and sister of Louise Turpin – accused of the horrendous abuse of her 13 children – have revealed their horrific upbringing and how it turned their once-naïve sibling into a cruel, sadistic psychopath.

“You hear people say sometimes the abused can become the abuser. I think that she’s just one of those that it did happen that way,” said Louise’s sister Teresa Robinette.

60 Minutes reporter Liam Bartlett joined Teresa and her brother Billy Lambert as they returned to their hometown of Princeton, West Virginia – or as they refer to it, the birthplace of the cycle of abuse that has forever tormented their family.

Teresa Robinette says she and her sister Louise suffered ongoing sexual abuse at the hands of their own grandfather. Picture: 60 Minutes (60 Minutes)

Louise is now accused to the horrendous abuse of her own children, aged 2 to 29. Picture: Supplied (60 Minutes)

“This looked like a happy home on the outside but inside it was miserable,” said Teresa.

“This is a house of horrors. This is where it all began.”

Louise and Teresa were repeatedly sexually assaulted by their grandfather, which was condoned and even encouraged by their own mother.

“My mum would take us to him daily,” Teresa revealed.

“There was no escape for us because you weren’t allowed to talk about it, because he had the money and the power. Basically, my mum lived off my grandfather for years.”

“She was pretty much selling us for money to live on.”

The sisters grew up with brother Billy in Princeton, West Virginia, but say their seemingly happy home was in fact miserable. Picture: Supplied (60 Minutes)

Teresa Robinette describes her childhood home in Princeton, West Virginia as a 'house of horrors'. Picture: 60 Minutes (60 Minutes)

Desperate to escape from her grandfather’s abuse, Louise moved to Texas when she was just 16 years old, alongside her much older boyfriend David Turpin.

It was here they began to expand their new family, having eight children in the space of fifteen years.

“We thought she had the perfect life, she had the perfect husband,” Billy told 60 Minutes.

“We thought she was happy.”

From the outside, the Turpins lived a life of wealth and success.

David was a highly paid engineer and would pay for Louise’s family to visit them for holidays every year. But then, in 1998 something shifted in the Turpin household.

Louise's brother Billy says he never suspected his nephews and nieces were subjected to such horrific treatment. Picture: 60 Minutes (60 Minutes)

Louise and David completely withdrew not only from their family, but also from the outside world.

They were secretly bankrupt which meant an end to the yearly holidays, and in the first of many signs that something sinister was going on, they began to home-school all eight of their children.

“Her excuse to us was the crime rates were always bad or the kids are getting picked on too much and I don’t like them feeling down on themselves,” said Billy.

Ricky and Shelly Vinyard and their two daughters Ashley and Barbara spent a decade living across the gravel road from the Turpins in Rio Vista.

They told Liam Bartlett that even with distance separating them, it was clear there was something disturbing about their new neighbours.

“Ashley would go over there and play, I think that she may have been the only friend that they ever had,” said Shelly.

At just 16, Louise escaped her abusive childhood home with much-older boyfriend, David Turpin. Picture: Supplied (60 Minutes)

“All the other kids would make fun of them because they said they smelled bad, they were dirty and had weird haircuts; they wore weird clothes.”

But it wasn’t long before the Vinyards told their children to keep their distance from the Turpins.

“I had come across the kids out there with Ashley and I introduced myself, and then I notice how white her hands were,” said Shelly.

“At first, I thought they were gloves. White gloves and I said, ‘I thought you had gloves on there for a minute!’”

“And she goes, ‘You wash to the wrist or else you’re wasting water.’ And the way she spoke was really strange like she might be a little slow.”

“She was telling you that she’d been told not to wash?,” questioned reporter Liam Bartlett.

“Past the wrist or you were wasting water.”

The children’s horrible existence was almost uncovered when the eldest sibling attempted to run away.

A neighbour picked her up and, due to her extreme malnourishment and lack of education, assumed she was mentally challenged and returned her to her parents.

“After that happened, you started seeing the kids outside again during the daylight and in the evenings and then they’d pull them back in,” Shelly revealed.

“And then after a couple of weeks, they withdrew them again.”

When questioned why they didn’t alerted authorities to the Turpins’ concerning behaviour, the Vineyards replied: “We thought about it but then again, you’re out in the country and you mind your own business and you figure they want their business kept to themselves and you don’t realise what you’re seeing.”

In 1998, Louise and David Turpin withdrew not only from their family, but also from the outside world. Picture: Supplied (60 Minutes)

The Turpins' neighbours in Rio Visto, Ricky and Shelly Vinyard, said it was clear there was something disturbing about the family. Picture: 60 Minutes (60 Minutes)

“Evil is deceptive. I mean, it can look good from a surface if you don’t get in there too deep.”

By 2010, David and Louise Turpin’s secret perversions were becoming more obvious in Texas, so they moved across the country to California. They had added another four children to their ever-growing brood.

What they left behind is something the Vineyards say they will never be able to erase from their memory.

“We walked off into the house, faeces all over the floor.”

“The desks were lined up where they had the little home school. They had the ABCs, the 123s on the walls. They had a giant whiteboard, but the house smelled of funk.”

“All the closets had padlocks. The refrigerators had padlocks. All the cabinets had padlocks. Everything in the house was locked down.”

The Vineyards also discovered unused bikes sitting in the car port that had rotted away.

“It was like mental torture, where you put the toy in front of a child but you can’t play with it.”

The children’s beds had rotted and were covered in ropes and chains used to tie them down.

Dead cats were found throughout the home.

“It was a house of horrors. A true house of horrors. It was right up under our nose and we didn’t see it.”

The Vineyards never reported their horrific discovery, and so David and Louise Turpin went on to not only have another child, but continue to escalate their abuse in Perris, south California.

Teresa Robinette says her sister and David had also been pulled into a vortex of new temptations, including partying, gambling and sexual exploits.

If found guilty, David and Louise face 94 years in prison. Picture: 60 Minutes (60 Minutes)

“Louise had called me. She just told me that her and David had walked away from the church and they had been looking into other religions. But then eventually they did dabble into witchcraft.”

“I knew they were making some wrong choices but I never in a million years would have thought that it had anything to do with danger to the kids.”

In the early hours of January 14 this year, David and Louise Turpin’s 17-year-old daughter escaped the family home and used a hidden mobile phone to call emergency services.

The state the children were discovered in shocked veteran police officers, legal experts and the wider community.

They were chained to their beds, fed once a day, bathed once a year and had no communication with the outside world.

The Turpin’s 29-year-old weighed just 37 kilograms. The 17-year-old had the IQ of a first grader.

It’s almost hard to believe, but the neighbours living just metres away denied any knowledge of the unfathomable conditions the children were living in.

The Turpins' 13 children are now in the care of the state. Picture: Supplied (60 Minutes)

For brother Billy Lambert that’s something too difficult to accept.

“I’m disappointed at the neighbours,” he told 60 Minutes.

“One said that they were marching in a circle at night-time upstairs and they saw them in the window.”

“To me that seems a little strange right there. I would at least go knock on the door and be like ‘Is everything ok?’”

“There was another neighbour that came forward that said that two of the older boys were digging in the trashcans at night. To me, how is that not a red flag?”

If found guilty, David and Louise Turpin face 94 years in prison for their sick crimes.

But their 13 children, who are currently in the care of the state, have already been dealt life sentences dealing with the psychological and emotional damage created by their wicked parents.