The parents of the children who were allegedly tortured and found shackled to their beds are said to have hidden their crimes behind the veil of homeschooling.
David and Louise Turpin are alleged to have held their 13 children hostage inside their various homes for years, for reasons that remain unclear.
Last week the children were found shackled to their beds by chains and padlocks after the couple's 17-year-old daughter escaped and called authorities, alerting them to the mistreatment they had suffered for years.
They were forbidden to use the toilet, forced to relieve themselves where they were and could only shower once a year while they were restricted to just one meal per day.
According to neighbours, the family seemed fairly normal and many were shocked to learn of the misfortune these children were forced to endure for so long.
There is one question neighbours and strangers alike are asking - how did they get away with this way of living for so long?
The answer? Homeschooling.
The children, aged two to 29, were taught at the family home in Perris, about 100km southeast of Los Angeles, after Mr Turpin officially registered a private school, the Sandcastle Day School, at the address in 2011.
The California Department of Education lists Mr Turpin as the school’s “principal” on its website. However, authorities said evidence suggested that only his children were taught there, News Corp reports.
The so-called private school was never inspected by education officials, and there is no legal requirement that they do so.
There was also no state official that came to test the children to see if they were meeting California's standard academic benchmarks.
While the education department said it was “sickened by this tragedy”, it stressed it had no legal power to “approve, monitor, inspect or oversee” the school.
Mr Turpin's parents told ABC News that the homeschooling was “very strict” and that they were expected to memorise long Bible passages.
Hundreds of journals have been seized as evidence by authorities as the children were ordered to write in them, even while chained up.
Riverside County district attorney Mike Hestrin said the children were so badly malnourished and abused that many of them were cognitively impaired.
“The children lacked a basic knowledge of life; many of the children didn’t even know what a police officer was,” Mr Hestrin said.
“A 17-year-old, when asked if there was medication or pills in the home, didn’t know what medication or pills were.”
The Coalition for Responsible Home Education (CRHE) keeps a database of homeschool abuse cases with 380 incidents of severe or fatal child neglect recorded since 2000.
“We would not say abuse is more common among home-schoolers, but when it does occur, there are fewer safeguards, less to stop it from spinning out of control,” CRHE executive director Rachel Coleman told Reuters.
Mr and Mrs Turpin have each been charged with 12 counts of torture, seven counts of abuse of a dependent adult, six counts of child abuse and 12 counts of false imprisonment. Mr Turpin faces an additional charge of performing a lewd act on a child.
They pleaded not guilty to all charges and are due back in court in February.