Louise Anna Turpin, 49, and David Allen Turpin, 57, have been arrested after authorities said their 13 children had been held captive in their home, with some shackled to beds (AFP Photo/Jose ROMERO)

A California couple has been arrested after authorities found a dozen of their malnourished children held captive in their home, with one as young as two and some shackled to beds in the dark, officials said Monday.

Authorities launched a torture probe and set bail at $9 million for the parents after a 17-year-old girl escaped the house on Sunday and called 911 using a cellphone found inside.

She was so "emaciated" that officers said they originally thought she was only 10 years old.

The 13 victims who had been held captive at the Perris, California home range in age from two to 29, the Riverside County Sheriff's Department said in a statement. They were not named.

"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 statement added.

"Deputies located what they believed to be 12 children inside the house, but were shocked to discover that seven of them were actually adults, ranging in age from 18 to 29. The victims appeared to be malnourished and very dirty."

The sheriff's office said "the victims were provided with food and beverages after they claimed to be starving."

The parents, 57-year-old David Allen Turpin and 49-year-old Louise Anna Turpin, were booked on torture and child endangerment charges.

Child Protective Services and Adult Protective Services assisted in the investigation.