Riverside County sheriff's Captain Greg Fellows described the reaction of 49-year-old Louise Turpin but did not know the reaction of the father, 57-year-old David Turpin.
The children, some of them chained to furniture, were described as weak and small for their age. Capt Fellows called it torture.
The abuse was discovered when a 17-year-old girl jumped out of a window and called 911 Sunday. The sheriff's captain said officers had never been to the home and neither had social service workers.
Corona Regional Medical Centre chief executive Mark Uffer said his facility was treating seven of the adult children. Mr Uffer said they are small and clearly malnourished but were stable and very friendly.
Turpin's father, James, said he was surprised by news of his son's arrest.
James and his wife Betty said that they are considered to be a good Christian family in their community and that added that "God called on them" to have as many children as they did.
The pair also said their grandchildren had "very strict homeschooling," and they would memorise long passages of the Bible, some of them aimed to learn the entire Bible.
James said all 13 children were his son's biological offspring and none were adopted.
David and Louise Turpin were arrested on Sunday on suspicion of torture and child endangerment. A court appearance is set for Thursday.
Thirteen siblings were rescued by police after a number of them were found chained to beds in "foul-smelling surroundings".
The 17-year-old girl called police after escaping from the home where she and her 12 brothers and sisters were locked up, some so malnourished officers at first believed all were children even though seven are adults.
The girl, who was so small officers initially believed she was only 10, called 911 and was met by police who interviewed her and then went to the family home in Perris, about 70 miles south-east of Los Angeles.
They found several children shackled to their beds with chains and padlocks in the dark, according to the Riverside County Sheriff's Department.
The children, ages two to 29, "appeared to be malnourished and very dirty," according to officers who arrested the parents. Neighbours said they were stunned by the arrests. Andrew Santillan, who lives around the corner, heard about the case from a friend.
"I had no idea this was going on," he told the Press-Enterprise of Riverside. "I didn't know there were kids in the house."
Other neighbours described the family as intensely private.
A few years ago, Robert Perkins said he and his mother saw a few family members constructing a Nativity scene in the Turpins' front yard. Mr Perkins said he complimented them on it.
"They didn't say a word," he said.
The Turpins filed for bankruptcy in 2011, stating in court documents they owed between 100,000 dollars (£72,500) and 500,000 dollars (£362,000), The New York Times reported.
At that time, Turpin worked as an engineer at Northrop Grumman and earned 140,000 dollars (£100,000) annually and his wife was a homemaker, records showed.
Their bankruptcy lawyer, Ivan Trahan, told the Times he never met the children but the couple "spoke about them highly."
"We remember them as a very nice couple," Mr Trahan said, adding that Louise Turpin told him the family loved Disneyland and visited often.
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