LOS ANGELES -- The grandparents of 13 starved and tortured siblings say 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 are still in shock from learning that her son and his wife were arrested this week, their children, ages 2 to 29, found malnourished with some in shackles.

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David and Louise Turpin, jailed on $9 million bail, are expected to make their first court appearance on Thursday, and could face charges including torture and child endangerment, authorities said. Prosecutors plan a news conference for earlier in the day.

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, "the 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 grandkids, who are hospitalized as they recover from their years-long ordeal.

An Elvis impersonator who performs weddings in Las Vegas is one of the few people who had direct dealings with the family.

"It's very disturbing because I felt like I did know them," said Kent Ripley, the Elvis impersonator who led the parents Louise Turpin, 49, and David Allen Turpin, 56, through at least three vow renewal ceremonies in recent years, most recently on Halloween, 2015. The couple was jailed on $9 million bail each. Charges that may include torture and child endangerment could come Wednesday and a court appearance is scheduled for Thursday, authorities said.

Ripley looked back at YouTube videos of the ceremonies after hearing the news, including two that show all the children dancing and smiling, with matching outfits and similar haircuts.

"Watching them now it's kind of haunting and disturbing," Ripley told The Associated Press in an interview Tuesday. "They all looked young and thin but I figured it was just their lifestyle. Maybe the activities they did, maybe because of their religious beliefs. I didn't get that in depth with them but I knew they were a fun family."

On Wednesday, authorities searched the couple's current home in Perris, 60 miles southeast of Los Angeles, where one of the daughters, a 17-year-old jumped out the window and called 911 on Sunday. 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 in 2011, and police said they were never called to either home, nor were any reports fielded by child protective services.

It's not clear what motivated the Turpins to live a secluded life with their large brood or what went on in the house.

Nor is it clear why the teen girl fled when she did, breaking a silence that had likely lasted years.

Psychiatrists say that even in cases of extreme deprivation, it's common for feelings of helplessness or confusion to lead to staying in place despite opportunities to flee.

"This happens all the time. The number of individuals who would immediately respond to an opportunity where they could get away is very small compared to the number of people who would have that paralysis and insecurity and confusion about what to do," said Dr. Bruce Perry, a psychiatrist and senior fellow at The ChildTrauma Academy in Houston.

The vulnerable girl might have been shamed, beaten or threatened with violence and only after many missed opportunities did she probably work up the courage to act, Perry said.

"It's pretty remarkable that she'd do that," he said. "The power that must have been exerted to keep an entire family like that for so long must have been pretty sophisticated."