They are facing numerous charges after their 13 children were found allegedly being held captive in their home, all were malnourished and some were shackled to furniture.
Authorities were reportedly "shocked" to find that some of the people trapped in the home were adults, and even estimated the teen who called police to be about 10 years old.
Police were alerted to the situation by the Turpins' 17-year-old daughter who reportedly managed to escape and called 911 using a cellphone she'd found in the house.
Investigators said that after interviewing one of the victims, they contacted her parents, who were "unable to immediately provide a logical reason why their children were restrained in that manner".
The six children were eventually transported to the Riverside University Hospital System (RUHS) for medical examinations and admitted for treatment. They described her as appearing only 10 years old and emaciated.
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".
They also said the children appeared to be malnourished and looked younger than their ages. "You just think that they were always amusing and private anyway, even before they had children".
"You can see mum and dad seem to be of healthy weight".
Neighbours in Perris, where modest but well-maintained homes are tightly packed on suburban streets, said they were stunned by the arrests.