"The abuse was rampant. Physical, sexual, emotional — we experienced all three. Some of it at the hands of the men, some of it at the hands of the wives." They spoke out as child protection workers continued to interview 416 children removed this week from the Fundamentalist Church of the Latter Day Saints ranch at Eldorado, Texas, because they were at risk of, or were already victims of, neglect and sexual abuse. The ranch is associated with self-proclaimed prophet Warren Jeffs, now serving 10 years' jail for facilitating the rape of a 14-year-old girl in an arranged marriage.

The Mackert sisters grew up alongside Jeffs in Colorado City, near Arizona's border with Mormon-dominated Utah. Former Utah journalist Andrea Moore-Emmett said 13 major groups practised polygamy, which has been abandoned by the mainstream Mormon church. Ms Moore-Emmett said she fled Utah after publishing a book, God's Brothel, detailing the abuse of women and children in fundamentalist communities. She said polygamy was "normalised" in Utah, where the sects were viewed simply as people practising their religion. "Women are vessels to be worn out in childbirth, and girls are having children at age 14, 15, 16," she said. "We have a high tolerance for religious freedom … and anything goes in the name of religion."

Kathleen Mackert, 50, who said she had undergone extensive therapy since leaving the group after her husband's work moved the couple away, said she was relatively lucky being forcibly married to a stepbrother only 10 years her senior. "Literally, one day I was called into my father's office and he told me God had given the prophet a revelation that I was to marry my brother," she said.

"Everything was controlled. Those girls there, they don't see a way out. When I was growing up the community was not nearly as closed off and fanatical as they are now, so it's my belief the abuse is even worse now. "The thing about that religion, it attracts a lot of people who are dysfunctional." Rena Mackert, 54, now lives in hiding in the US. She said her mother's family had for generations practised polygamy.

"You are taught that you can all but kill a child for deliberate disobedience. The men have their power taken away by (Warren) Jeffs. The only thing they have control over is their wives and children. It's power, it's control and it's sex," she said. "This is about under-age children being bartered as sex slaves, taken across state lines to marry into other compounds. It's just that they tried to cover it up under the label of freedom of religion."

The Utah Attorney-General's office has employed special investigators to look into the sects and claims some responsibility for last year's prosecution of Jeffs. Attorney-General spokesman Paul Murphy said several new probes were under way and Arizona was prosecuting eight men for sex offences relating to under-age marriage. He said the families supported themselves through welfare claims. "I met a woman the other day who had 17 children, and another with 14. Multiply that by several wives and you have a pretty big family." Ms Moore-Emmett was critical of Utah officials and said the state did little because polygamy was so normalised. "The politicians are Mormon. Mormons have abandoned polygamy. However, it's in their scripture and they all expect to live it in the hereafter."

Ms Mackert said welfare workers dealing with the Eldorado children would need to avoid make-up, jewellery and wearing their hair loosely — all "signs of the devil" — or else they would not be trusted.