The teen fled her Perris house early Sunday and called from a cellular device she took from her suburban tract house, according to the Riverside County Sheriff's Department. The discovery was made after a 17-year-old girl escaped the house in Perris around 100 kilometres east of Los Angeles.
Their parents, David Allen Turpin, 57, and Louise Anna Turpin, 49, were arrested and charged with nine counts each of torture and 10 counts each of child endangerment, and held on more than $11 million bail.
The parents were arrested and booked on charges of torture and child endangerment.
The sheriff's office said first responders initially believed everyone in the room to be a minor due to their malnourishment, and that the 17-year-old only appeared to be around ten.
She had reportedly claimed that she alongside her 12 siblings were been held captive in their home by their parents against their will.
They were very protective of the kids.More news: South Africa: Cape Town slashes water use amid drought
Media outlets cited the Turpins' neighbors as saying that "they seemed like the flawless family".
It's unclear how long the children were forced to live under those conditions, but officials said they believe it was for a "prolonged period of time". All 13 people were admitted to nearby hospitals for treatment.
The seven adult children were being cared for at Corona Regional Medical Center, said CEO Mark Uffer.
California Department of Education records show a private K-12 school, called Sandcastle Day School, listed with David Turpin as principal.
Meanwhile, Twitter users have been quick to react, with majority saying that they were shocked about the news.