Parents of captive siblings to make court appearance in California
David Allen & Louise Anna Turpin w:Children (Facebook)

A Southern California couple accused of keeping their 13 children captive and malnourished in the family's squalid suburban home were scheduled to make a first courtappearance on Thursday.

David Turpin, 57, and his wife Louise Turpin, 49, were arrested earlier this week after their emaciated 17-year-old daughter climbed out a window of the family's home in Perris, 70 miles (113 km) east of Los Angeles, and called the 911 emergency number on a cell phone.

Police who responded to the home in an otherwise unremarkable subdivision of Perris say they found the girl's 12 siblings, ranging in age from 2 to 29 years old, being held in "horrific" conditions, some chained to beds.

David and Louise Turpin were each charged with nine counts of torture and 10 counts of child endangerment and are being held on $9 million bail.

At their initial court appearance the couple was expected to be formally apprised of the charges against them and enter a plea.

Before the hearing, the Riverside County District Attorney's office will hold a news conference at 11 a.m. local time (1900 GMT).

David Turpin's mother, Betty Turpin, told Reuters on Wednesday that the family had engaged an attorney, who advised them not to speak about the case.

Investigators this week have conducted an exhaustive search of the home, where the children also were apparently home schooled.

The California Department of Education lists the Turpin address, where the family has lived since 2014, as the location of the Sandcastle Day School, with David Turpin as principal.

Experts say it may have been easier for the parents to shield their children from scrutiny because they were home-schooled.

(Writing by Dan Whitcomb; Editing by Lisa Shumaker)