The Southern California husband and wife accused of starving and shackling their kids were also wannabe swingers, a relative claimed Monday.
Louise Turpin, 49, went through a spiritual and sexual awakening around the time of her 40th birthday, and she was all too eager to share it with her sister Teresa Robinette, the sibling revealed on NBC's "Megyn Kelly Today."
In one particularly bizarre call between 2008 and 2010, Louise claimed she and husband David Turpin met a strange man online and arranged a hotel rendezvous with him in Huntsville, Ala., Robinette said.
David allegedly dropped her off for the tryst.
"What makes it even worse and even weirder is that exactly one year to the date of the anniversary that she did that, she called me and thought it was funny that David was taking her back to the exact same hotel room, the exact same bed she slept with this man in, so David could sleep with her in the same bed," the sister said.
Robinette said it all happened around 2009, when the couple was living in Texas with their already-large brood.
In a series of phone calls, Louise seemed eager to share her escapades with Robinette, who was the "wild child" in the family growing up, the sister said.
"She had 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, you know, quit going to church, and they didn't trust the church anymore. They were experimenting with different religions," Robinette said.
Louise allegedly reported that her older kids were helping to take care of the younger children, so she and David were free to make up for lost time and sow their "wild oats," Robinette said.
"They had called me the first time they ever went to a bar," the sister said. "She called me the very first night she was drunk. She was very giggly."
Then Louise dropped the bomb that she was meeting the man for sex in Huntsville with David's encouragement.
"It was a very weird thing to me that I would never do," Robinette said. "I told her I thought it was a mistake."
Robinette broke down crying during the TV interview as she described how a male relative sexually abused her and several members of her family, including Louise and their mom.
"It was always a dark family secret that he did this," she said.
"A very, very close family member that we should haveloved and trusted, he abused my mother and - sexually abused my mother - and then me and Louise, Elizabeth and a few of our cousins in the family," said Robinette, choking up.
Elizabeth Flores is another sister who also has spoken out in the wake of Louise's arrest last week.
"That was a situation that was ongoing for me and my sisters only because my mother had so much abuse in her life," Robinette told Kelly.
"I think that her mind was, she was still going through it as an adult. And my mother still took us around this person, a lot, including Louise."
Louise and David Turpin, 57, were arrested Jan. 14 after their 17-year-old daughter jumped out a window of their home in Perris, Calif., and called 911 with a deactivated cellphone.
Investigators rushed to the house, about 60 miles southeast of Los Angeles, and found 12 more Turpin siblings living in a foul-smelling dungeon where kids were regularly starved, beaten and locked up with chains and padlocks, authorities said.
Three were in shackles when officers arrived.
Cops said the 13 siblings all appeared to be minors at first. They later learned seven were adults ranging in age from 18 to 29.
Years of starvation and abuse had stunted the kids' growth and even caused cognitive impairment and nerve damage, authorities said.
The 29-year-old daughter weighed just 82 pounds when she was rescued, Riverside County District Attorney Michael Hestrin said.
One of the children at age 12 was the weight of an average 7 year old, he said.
The couple has pleaded not guilty to multiple counts of torture, abuse and false imprisonment.
David was also charged with one count of a lewd act on a child 14 or younger.
"We are alleging David Turpin touched one of the victims in a lewd way by using force or fear," Hestrin said.
If convicted as charged, the parents each face 94 years to life in prison.