A man and a woman have been arrested in California, accused of keeping their children shackled to beds with chains and padlocks in "dark and foul-smelling surroundings."

According to the Riverside County Sheriff's Department, a 17-year-old escaped from the home in Perris early Sunday morning and called 911, telling emergency officials that her parents were holding her 12 siblings captive.

Police said that when officers met with the caller, she "appeared to be only 10 years old and slightly emaciated."

"Further investigation revealed several children shackled to their beds with chains and padlocks in dark and foul-smelling surroundings, but the parents were unable to immediately provide a logical reason why their children were restrained in that manner."

The children, who police say "appeared to be malnourished and very dirty" range in age between two and 29 years old.

None had any idea of horrors allegedly visited upon couple's young and adult children for years 1:03

"Deputies located what they believed to be 12 children inside the house, but were shocked to discover that seven of them were actually adults," the release said.

"The victims were provided with food and beverages after they claimed to be starving."

David Allen Turpin, 57, and Louise Anna Turpin, 49, were arrested for violating California laws around torture and child endangerment. Both were detained, with bail set at $9 million US each.

It wasn't immediately known if the pair had attorneys. They were scheduled to appear in court Thursday morning.

The Press-Enterprise, an area newspaper, reported that county records indicate the couple are owners of a property at 160 Muir Woods Rd. in Perris, a city located about 120 kilometres southeast of Los Angeles.

According to data about private schools accessible through the California Department of Education website, David Turpin is listed as the principal of Sandcastle Day School, which is registered at the same address.

Torture/Child Endangerment Investigation in Perris <a href="https://t.co/LIm8s3OHbk">https://t.co/LIm8s3OHbk</a> —@RSO

Six of the couple's children are minors, while the other seven are over 18, police said.

The 2016-17 information says the school is registered as a co-educational, non-religious school ranging from Grade 1-12, with a total enrolment of six students.

Neighbours stunned

Neighbours said they were stunned by the arrests. Andrew Santillan, who lives around the corner, heard about the case from a friend.

"I had no idea this was going on," he told the Press-Enterprise. "I didn't know there were kids in the house."

Other neighbours described the family as intensely private.

A few years ago, Robert Perkins said he and his mother saw a few family members constructing a Nativity scene in the Turpins' front yard. Perkins said he complimented them on it.

Members of the news media stand outside the Turpin's home in Perris, Calif., on Monday. (Mike Blake/Reuters)

"They didn't say a word," he said.

The Turpins filed for bankruptcy in 2011, stating in court documents they owed between $100,000 and $500,000, The New York Times reported. At that time, Turpin worked as an engineer at Northrop Grumman and earned $140,000 annually and his wife was a homemaker, records showed.

Their bankruptcy lawyer, Ivan Trahan, told the Times he never met the children but the couple "spoke about them highly."

"We remember them as a very nice couple," Trahan said, adding that Louise Turpin told him the family loved Disneyland and visited often.

The parents are expected to appear in court Thursday.