David Turpin and Louise Turpin as they are shown in what appeared to be their wedding day. Photo posted on Facebook in 2016. Facebook/davidlouise.turpin

Two US parents have been charged with torturing their 13 children. The children, ranging from the age of 2 to 29, were held captive inside their California residence, with some found shackled to their beds.

On Sunday, a 17-year-old girl escaped from her home and called the emergency service 911. She said she and her 12 brothers and sisters were being held captive by their parents. The officers from the Perris Police Department first thought the girl was just 10 years old as she looked slightly emaciated. After interviewing the teenager, the police contacted their parents, David Allen Turpin, 57, and Louise Anna Turpin, 49.

The police found some of the children in the house shackled to beds with chains and padlocks. They were also malnourished and in unclean conditions. All 12 children were first thought to be minors, but further inquiries revealed that seven of them were actually adults aged 18 to 29.

“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 police said in a statement. “The victims appeared to be malnourished and very dirty.”

The 13 victims were provided with food and drink after they told officers they were starving. Six children were taken to the Riverside University Hospital System for treatment and medical examinations. The seven adults were taken to the Corona Regional Medical Center also for examination and medical treatment. The parents, on the other hand, were detained and taken to the station for further investigation. They were charged with nine counts of torture and 10 counts of child endangerment each.

They had not immediately provided a logical reason why they restrained and allegedly tortured their children. Their bail was set at US$9 million (AU$11.3 million) each. They are expected to appear in court on Thursday.