The father accused of torturing his 13 children once willingly drove his wife interstate so she could have sex with another man they had met online so she could "sow her wild oats", her sister has revealed.
David and Louise Turpin were each charged with 37 counts of torture, abuse and false imprisonment last week after police found their children tied up and malnourished inside their Southern Californian home.
Now Louise's sister, Teresa Robinette, has revealed details about the couple's sex life, including that they marked the anniversary of her affair by sleeping together in the same hotel bed.
Speaking on Megyn Kelly Today, Robinette said her sister, now 49, lived a God-fearing life, free from the vices of drugs or alcohol, until she decided to experiment when she turned 40.
"I was always considered as a teenager — the wild child — and she had never experimented in that and she never smoked a cigarette or drank a drink of alcohol or anything, and close to her 40th birthday or around that time period she called me and she thought it was cool that they had quit going to church and that they didn't trust the church any more," Robinette said.
"They were experimenting with different religions and at the time and … the older children were helping her take care of the younger children so her and David could sow those wild oats that she didn't sow when she was younger.
"So, they had called me the first time they ever went to a bar, she called me the very first time she was drunk, she was very giggly."
Mrs Turpin also revealed to her sister that — during that period of experimentation — Mr Turpin willingly drove her to another state to have sex with a man they met on the internet.
"It was a very weird thing to me that I would never do," Robinette said.
"She told me that her and David had met a man online from Huntsville, Alabama, and that they were on their way there to meet him and that she was going to sleep with him, and that David was OK with that … David dropped her off.
"She met this man at a motel, slept with him, and what makes it even worse and even weirder is that exactly one year to the date, the anniversary that she did that, she called me and thought that it was funny that David was taking her back to the exact same hotel room, the exact same bed that she slept with this man in so that David could sleep with her in the same bed."
Robinette became tearful when she revealed that she, her sisters, her mother and some of her cousins had all been sexually abused by a "very, very close family member", whom she declined to name.
"It's always been a big secret in our family, the adults in our family protected him because he was family," she said.
Robinette said she would not forgive her sister for what she had allegedly done to her children.
"Louise no longer exists to me. Her and David are dead to me," she said.
"The children, I hope, when they come out of from where they're at now, our hope is that they all can lead some sort of normal or happy existence.
"They obviously have never known happy, except maybe the older ones for a little while, but my main hope is that I can put my arm around them and just tell them that they have family that loves them, that's not deranged, that this is what it's supposed to be like."
Riverside Country district attorney Mike Hestrin alleged last week that Mr and Mrs Turpin abused their children for years, depriving them of food, locking them up with chains and padlocks and refusing to allow them access to the toilet.
"This is severe, emotional, physical abuse ... This is depraved conduct," he said.
Mr and Mrs Turpin have pleaded not guilty to the charges, which includes an additional allegation that Mr Turpin performed a lewd act on a child.
A former neighbour in Rio Vista, Texas, told the Los Angeles Times that the Turpins never socialised and rarely left their Perris home, about 100km south-east of Los Angeles.
Ricky Vinyard said the Turpins kept the lights on at all hours with the blinds drawn.
He said one Christmas they bought eight new children's bicycles that sat outside, unused.
- with AP