Franke, whose now-defunct 8 Passengers channel followed her family, was arrested on Wednesday in Utah and was taken into custody.

Her 12-year-old son climbed out of a window and ran to a neighbour's house asking for food and water, according to a court filing by the Santa Clara-Ivins Public Safety Department.

According to the document, the neighbour saw duct tape on the boy's ankles and wrists and called the police.

Franke's 10-year-old daughter was later found malnourished and was also taken to the hospital.

Speaking to Sky News's sister outlet NBC News, two of Franke's neighbours said people in the community had previously alerted child services.

"Everyone is just breathing a collective sigh of relief because we thought they were going to come out of that house with body bags," a male neighbour said.

Neighbours accused Franke of withholding food as a punishment for her children - a behaviour that was also shared on her YouTube channel.

They also claimed that, after her husband was out of the home, Franke would leave the house for weeks at a time, with the children inside.

"I remember that she took away their Christmas one year," the male neighbour said, "and she would say things like 'They're not repenting correctly,' which is a Mormon term for 'they're sinning.' Just complete insanity."

On Thursday, a judge denied Franke bail after a detective cited "the severity of the injuries of her two kids located in the home," and told the judge the Department of Child and Family Services had taken four of Franke's children into custody with the officer yet to speak to two of them.

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'We did as much as we could'

After her arrest, Franke's sisters said they are "all on the same page" about their sibling and are glad that the children are now safe.

In a now-deleted YouTube video titled 'My statement on my sister Ruby Franke', Bonnie Hoellein, who is also a social media personality, said "we all did as much as we could, legally," when speaking about protecting her niece and nephews.

"For the last three years, we have truly clung on to each other and offering support to one another, and I don't think any of us could've seen this coming.

"I know that timing is everything, and I know that they will be taken care of. I know the kids will be OK and that our family will be OK."