A nondescript, burnt orange house in Southern California — similar to many others on the same street — turned out to be a prison for 13 siblings.

Now questions abound over why the Turpin children were allegedly held captive by their parents — and how no one else seemed to know.

What we know

A 17-year-old escaped through a window

If not for a daring bolt by a 17-year-old girl, she and her siblings might still be trapped.

The teen “appeared to be only 10 years old and slightly emaciated,” the Riverside County Sheriff’s Department said.

Using a cell phone she grabbed from the house, the girl tipped authorities off to a gruesome scene.

Some children were chained to their beds

When authorities arrived at the four-bedroom house in Perris, they found some of the children shackled with chains and padlocks, the sheriff’s department said.

Conditions inside the house were filthy, as were the siblings. They “appeared malnourished and very dirty,” authorities said.

The 13 siblings range in age from 2 to 29 — but the seven adults were so emaciated they looked like children.

The parents have been charged

David and Louise Turpin are charged with torture and child endangerment. Bail was set at $9 million each.

Riverside County sheriff’s deputies had not had previous contact with the couple, Capt. Greg Fellows said.

The children were apparently home-schooled

The father, David Turpin, ran a private school out of his home called Sandcastle Day School, according to the California Department of Education. Turpin is listed as both the administrator and principal.

They looked happy in vacation photos

Perhaps the oddest juxtaposition in this case is the cheerful family photos contrasted with the apparent horror of their home life.

One photo, taken at the parents’ wedding vow renewal in Las Vegas, showed a dozen beaming siblings and a baby, with all the boys wearing identical suits and the girls in matching dresses.

What we don’t know

The parents’ side of the story

It was not immediately clear if the suspects had attorneys. They have a court hearing scheduled for Thursday.

What other relatives may have known

David Turpin’s mother, Betty, said she doesn’t have any information about the case.

But she said “we feel like one side of the story has been reported. This is a highly respectable family.”

For example, the siblings wore identical outfits based on gender to help “keep up with the kids” during outings, she said.

And when the family went out, the couple would line the children up according to age, and the parents took their positions at the front and back of the line.

How long the children were held captive

The conditions of the Turpin children suggest they’ve been held captive for a “prolonged period of time,” said Susan von Zabern, spokeswoman for the Riverside County Department of Public Social Services.

But it’s not clear exactly how long the siblings were kept in filthy conditions.

How the parents supported the 13 children

In 2011, the Turpins filed for bankruptcy. At the time, David Turpin listed his income as a Northrop Grumman engineer as $140,000.

His wife’s occupation was listed as a homemaker.

The couple had about $240,000 in debt, which was mostly from credit cards, the bankruptcy documents state.

But photos posted on Facebook show the whole family took several vacations in recent years. And the children joined their parents when they renewed their vows at Las Vegas’ Elvis Chapel in 2013 and 2015.