In court documents released on Tuesday, child welfare officials allege that the site was rife with sexual abuse and that young girls were groomed to be "spiritually married" at puberty.
"There is a widespread pattern and practice of the YFZ Ranch in which young, minor female residents are conditioned to accept and expect sexual activity with adult men at the ranch upon being spiritually married to them," investigator Lynn McFadden wrote.
The cycle is continued when boys on the ranch reach adulthood and are "spiritually married" to young girls, "resulting in them being sexual perpetrators", she added.
Children were also deprived of food, locked in cupboards and physically beaten as punishment for breaking rules, investigators claim.
'Broken ribs'
According to the court papers, the 16-year-old girl who made the calls that triggered the raid said she had been sexually assaulted by her husband, who would also beat her "whenever he got angry".
The girl told investigators she had been married to her 49-year-old husband at age 15 and had already had one child. Eight months later, she was pregnant again, she said.
She recounted how her husband had choked her and hit her, on one occasion breaking several ribs. Other women in the house would hold her baby while he beat her, she said.
"She reported that church members have told her if she leaves the ranch, outsiders will hurt her, force her to cut her hair, to wear make-up and clothes and to have sex with lots of men," Ms McFadden wrote.