The parents of 13 siblings who were allegedly held in captivity in their family’s Southern California home were charged on Thursday with committing years of torture and abuse that left their children malnourished, undersized and with cognitive impairments.

“Severe, emotional, physical abuse,” Riverside County District Attorney Mike Hestrin said in announcing numerous charges against David Allen Turpin, 57, and Louise Anna Turpin, 49. “This is depraved conduct.”

Prosecutors filed 12 counts of torture, seven counts of dependent adult abuse, six counts of child abuse and 12 counts of false imprisonment against the couple. David Turpin was additionally charged with one count of a lewd act on a child under age 14.

The victims range in age from two to 29. The charges involve acts in Riverside County dating to 2010.

The torture and false imprisonment charges do not include the two-year-old, Mr Hestrin said.

The district attorney said the couple chained their children as punishment.

The house where the Turpins lived with their children (Alex Gallardo/AP)
The house where the Turpins lived with their children (Alex Gallardo/AP)

A 17-year-old daughter who climbed out a window on Sunday and called 911 on a mobile phone had plotted her escape for two years, he said. Another sibling escaped with her but turned back out of fear.

Mr Hestrin said all 13 victims were severely malnourished and as a result some have cognitive impairment and a lack of basic knowledge. He said a 29-year-old female victim weighed 82lb.

The victims were not allowed to shower more than once a year, he said.

In an interview, grandparents of the children said their son’s family looked happy and healthy when they last visited California six years ago.

“They were just like any ordinary family,” said Betty Turpin, the 81-year-old mother of David Turpin. “And they had such good relationships. I’m not just saying this stuff. These kids, we were amazed. They were ‘sweetie’ this and ‘sweetie’ that to each other.”

Betty Turpin and her husband, James Turpin, of Princeton, West Virginia visited her son’s family for five days at their previous home in Murrieta, California.

Betty Turpin told the Southern California News Group on Wednesday that they were still in shock from learning that her son and his wife were arrested.

Betty Turpin said her son told her he had so many kids because God wanted him to. She said her son shared her Pentecostal Christian faith but he wasn’t affiliated with a church in California.

“I feel they were model Christians,” she said. “It’s hard to believe all of this. Over the years, the Lord knows what happened.”

James Turpin said during their visit, “they all looked to me well-adjusted. They weren’t skinny or nothing. They were joyous to see us”.

He said they were dealing with social workers in attempting to connect with their grandchildren, who are hospitalised as they recover from their ordeal.

On Wednesday, authorities searched the couple’s current home in Perris, 60 miles southeast of Los Angeles. Investigators removed dozens of boxes, what appeared to be two safes and pieces of a bed frame.

Some siblings were shackled to furniture in the foul-smelling four-bedroom home that looked perfectly normal from the outside.

The Turpins have lived in two Riverside County communities since moving to California, and police said they were never called to either home, nor were any reports fielded by child protective services.