A couple accused of locking up and starving their 13 children had so many kids because it was God's calling, the siblings' grandparents claim.
David, 57, and Louise Turpin, 49, were arrested on charges of torture and child endangerment after their 17-year-old daughter escaped the home and alerted police.
The siblings, aged two to 29, were "very dirty" and some were chained to their beds when they were found by stunned police officers, who thought the seven adults were children because they were so malnourished.
Grandparents James and Betty Turpin have said they were shocked by the allegations, describing their son, daughter-in-law and grandchildren as a good Christian family who were "highly respected".
"God called on" the couple to have as many children as they did, the grandparents added.
The couple got married when Louise Turpin was just 16 years old, it was reported.
The grandparents have given some insight into what was happening inside the home in Perris, California, and have insisted "they were surprised and shocked" when they found out about the claims.
They told ABC News that the children were given "very strict home-schooling" and they would memorise long passages of the Bible, with some striving to memorise it in its entirety.
The grandparents last saw the family about five years ago when they visited them in California, saying the children "looked thin" at the time but the Turpins seemed like a "happy family".
Since then they had kept in touch with their son by phone, but they had not spoken to their grandchildren because their parents would often call when they weren't with the kids, they said.
Betty Turpin said the couple went on holidays, including to Disneyland, with all of their children, and they usually dressed the same for safety reasons.
One image from a family trip shows the children and parents in numbered "Thing" T-shirts based on the "Thing 1" and "Thing 2" characters in the Dr Seuss book The Cat in the Hat.
The children would be lined up according to age, with one parent at the front of the queue and the other at the back because it was easier "to keep up" with them, Betty Turpin added.
She told CNN: "They were very protective of the kids. This is a highly respectable family."
Neighbours have said the children appeared "afraid" and some were seen digging for food in rubbish bins.
They told of strange activities at the reclusive family's home - with one comparing the Turpins to the fictional vampire family in the Twilight books and films because "they only came out at night", they were pale and they would avoid conversation.
But horrified neighbours insist it was just odd behaviour and there was nothing untoward that would have suggested something sinister was happening inside the family's large bungalow.
Neighbours told CBS2 News that they saw some of the children digging for food in rubbish bins, and picking up trash around the family's home.
They said the children were shy and pale, but did not appear to be in poor health.
Police were alerted at 6am on Sunday when the "slightly emaciated" 17-year-old girl escaped with a mobile phone from inside the house and called 911, claiming her 12 brothers and sisters were being held captive by her parents.
A spokesman said in a statement: "Deputies located what they believed to be 12 children inside the house, but were shocked to discover that seven of them were actually adults."
Some of the children were allegedly shackled to their beds with chains and padlocks. Of the couple's children, seven were adults, aged 18 to 29.
When officers found the girl they thought she was 10 due to her small size.
Police then went to the home where they found “several children shackled to their beds with chains and padlocks in dark and foul-smelling surroundings".
The children were taken to a police station where they were given food and drinks after they told officers they were starving. They were then taken to different hospitals for treatment.
Police said the parents “were unable to immediately provide a logical reason why their children were restrained in that manner".
Video clips posted online shows the couple renewing their vows at the Elvis Chapel in Las Vegas, complete with an Elvis Presley impersonator, in 2011, 2013 and 2015, when they celebrated 30 years of marriage.
The children joined them at the last two renewals, with the girls wearing matching plaid dresses and the boys in suits at the 2015 event.
In the video and holiday photos, the boys have bowl haircuts like their father, while the girls all have long brown hair.
Neighbors said the Turpins and their children rarely emerged from their unkempt home in the newly-built development of closely spaced single-family ranch-style houses.
Wendy Martinez, a 41-year-old housewife, said her only contact with them came as she passed the house at night in October.
Four children were installing sod, or turf, in the unkempt garden while the mother watched from the door, and none responded when Martinez said hello.
Martinez said of the children: "They were very, like, afraid. Like they had never seen people before."
Neighbour Kimberly Milligan, 50, told the Los Angeles Times that the children she saw were very pale and she thought it was strange that she never saw them playing outside.
She also told how she said hello to pre-teen children putting up Christmas lights at the home about two years ago, and something didn't seem right.
She said: “They looked at us like a child who wants to make themselves invisible."
The family had also been seen installing a nativity scene in front of their home a few years ago, but didn't speak to neighbours or passers-by.
On social media, David and Louise Turpin regularly posted photos of what appeared to be a happy family, with images from their trips to Disneyland and Las Vegas, and snaps of the couple and their children.
One photo shows a baby wearing a T-shirt reading "Mommy loves me".
Stunned neighbours admitted they were left wondering how they failed to realise they were living next to an alleged house of horrors on the cul-de-sac.
MIlligan said: “We’re not acres apart. How did no one see anything?”
Andrew Santillan told the Press Enterprise: “I had no idea this was going on. I didn’t know there were kids in the house.”
She said: “They only came out at night. They were really, really pale.”
Nicole Gooding told CBS2: “Nonchalant, looked like they were having fun like a regular family."
The home was registered as a private, non-religious school called Sandcastle Day School, with David Turpin listed as its principal.
According to the registration the school had six students and was founded in the 2014-15 school year.
In recent years, David and Louise Turpin had regularly renewed their wedding views with a Las Vegas Elvis impersonator, who said he didn't notice anything alarming about the family at the chapel.
The impersonator, Kent Ripley, told CBS2: "The family kept growing, so I figured in a couple more years I’d see them again, and then I hear the news today."
The Turpins had lived in their home in Perris, about 70 miles east of Los Angeles, for several years, having previously lived in Texas.
They had twice declared bankruptcy, with the latest filing coming in 2011, when the family lived in nearby Murrieta, it was reported.
David Turpin had worked as an engineer at Northrop Grumman, a global aerospace and defence technology company, in San Diego, and had worked for Lockheed Martin until 2010, the Los Angeles Times reported.
His parents have said he was a computer engineer who graduated from Virginia Tech and had once worked for General Dynamics in Texas.
Lawyer Ivan Trahan, who represented the couple in 2011, told the Times that David Turpin had a "relatively high" income, but had trouble keeping up with his expenses because he had so many children.
He told CNN that the couple didn't seem upset that they were going through bankruptcy.
He added: "They came with a lot of debt. We just knew there was no way they could make their payments.
He said the parents "spoke lovingly of their children" and showed him photos from a trip to Disneyland in Anaheim.
Bankruptcy documents seen by the Times reveal David Turpin earned more than $140,000 in 2011, but his expenses were $1,000 greater than his take-home pay.
Louise Turpin was listed as a homemaker with no income.
The couple listed about $150,000 in assets, debts of about $240,000, including a foreclosed farm in Rio Vista, Texas, CNN reported.
They purchased their four-bedroom, three-bathroom house in Perris in August 2014 for $351,000, the Press-Enterprise reported.
The 2,388-square foot home was built in 2013.
David and Louise Turpin are being held in custody on nine counts of torture and 10 counts of child endangerment.
Their bail has been set at $9 million (£6.5 million) each and they are due to appear in court on Thursday.
Police believe the 13 siblings are the couple's biological children. Child and adult protective services workers were helping police with the investigation.
The Riverside County Sheriff's Department is expected to release more details at a press conference later Tuesday.