Until recently, Rodney Holm, a police officer, shared a five-bedroom home in Hildale, Utah, on the Arizona border, with his three wives and their 20 children. Then Mr. Holm's third and youngest wife, Ruth Stubbs, left in December, with their two children.
Mr. Holm sued for custody of the children. That gave rise to a legal battle infused not only with the usual wrenching accusations of abuse and neglect but also with serious questions about religious freedom, the sexual exploitation of teenagers by religious institutions and a law enforcement official's obligations to obey the law in his personal life.
Ms. Stubbs said she was ordered to marry Mr. Holm in 1998 by Rulon Jeffs, the leader of a breakaway Mormon sect known as the Fundamentalist Church of Latter-day Saints. It has thousands of adherents and dominates the twin towns of Hildale and Colorado City, Ariz.
"I made an appointment with the prophet," Ms. Stubbs said, referring to Mr. Jeffs. She said she had hoped to gain his approval to marry a young man she loved. But Mr. Jeffs, after considering the request, came to another conclusion.
"It comes to me that you belong to Rod," Ms. Stubbs said Mr. Jeffs told her. "He said I'd lose my salvation if I didn't marry him."
Ms. Stubbs was 16. Mr. Holm, then 32, already had two wives, one of them Ms. Stubbs's older sister, Suzie Holm.
William G. Walker, a Tucson lawyer, represents Ms. Stubbs. He has also represented 16 people who say they have been abused by Roman Catholic priests, and he sees some similar issues and some differences.
"There is clearly abuse going on, and it's clearly sexual abuse," Mr. Walker said. But while the accusations against Roman Catholic dioceses have centered on inadequate supervision of errant priests and on institutional cover-ups, Mr. Walker said that the abuse here was inherent in the doctrine of the sect.
"This is policy that comes from the top," Mr. Walker said. "It is a dictate from above: If we command it, thou shalt have sex with underage women."
Mr. Holm's lawyer, Rodney R. Parker, acknowledged that the church's practices — which are sharply at odds with those of the much larger Mormon Church, which officially abandoned polygamy in 1890 — posed serious legal questions. But he said the custody dispute was not the place to resolve them.
"Bill Walker has a broader agenda in wanting to file a civil lawsuit, and all of this is a sort of prelude to that," Mr. Parker said. "It is really unfortunate that these two little children are being caught in the middle of something like that."
Ms. Stubbs married Mr. Holm in a religious ceremony called a sealing, which is not recognized by the state. Mr. Holm's first two wives attended, wearing bridesmaid's dresses, Ms. Stubbs said.
After that, Ms. Stubbs said, Mr. Holm kept to a schedule. As she put it in an affidavit, "each wife, if not pregnant, would have sex with the petitioner, in the house, approximately every third night."
The logistics were straightforward. "He had clothes in each of our rooms, and he took a shower bag with him," she said. Ms. Stubbs's children, Miranda, 2, and Winston, 1, were born soon after. She expects a third child any day now.
Ms. Stubbs said Mr. Holm controlled the details of her life.
"I was totally forbidden from seeing any of my relatives because they were apostates," she said. "I'd get in trouble for eating a candy bar if I didn't ask, any caffeine, any junk food, any soda."
Bigamy and adultery are crimes in Utah, although they are seldom prosecuted. The most serious accusation against Mr. Holm is that he had sex with a minor. In Utah, it is a felony for someone who is 10 or more years older to have sex with someone who is 16 or 17. This does not apply to lawful marriages, and Utah does allow marriages involving minors as young as 16 if the minor has permission from a parent and the court.
In a deposition in the custody case, Mr. Holm invoked his Fifth Amendment right against being compelled to incriminate himself when asked about his sexual relationships with his wives and about whether he had sex with Ms. Stubbs while she was a minor, but he acknowledged that he is the father of her children.
Mr. Holm had also declined, he said, to answer similar questions this spring in an interview with Ron Barton, who investigates polygamy for the Utah attorney general's office.
Mr. Holm testified that he did not learn it was a crime to have sex with a 16-year-old until Mr. Barton told him.
Mr. Barton said he could not comment on or confirm the existence of an investigation. Mr. Parker, Mr. Holm's lawyer, declined to comment on the possibility of criminal charges against his client.
Ms. Stubbs said she left Mr. Holm because her children were neglected and mistreated. The 20 children in the house were often supervised by a single adult, she said, while the other three adults went to work.
Judge James L. Shumate of Utah District Court recently heard arguments about temporary custody arrangements. Mr. Parker said he argued that Mr. Holm's religious convictions and living arrangements were but one factor to consider.
"Where one or more parents have religious views that are offbeat, the question for the court is whether that has an impact on what is in the best interests of the child," he said. "It does not by itself disqualify a parent."
Mr. Walker argued that the children should not be in a home where the living arrangements violated the law.
Judge Shumate compromised. He allowed the children to visit their father every other weekend, but he ordered Mr. Holm not to have sex with his second wife, Wendy Holm, while the children were under his roof, because the state recognizes only his first marriage. Neither side was pleased with the ruling.
"I don't like my children going up there," Ms. Stubbs said. "I don't like them being with the other mothers. I don't know what they're being taught. I know Rod still wants to teach them polygamy."
Mr. Parker was puzzled by the ruling. "I don't know how his relations with Wendy bear upon the best interests of a 2-year-old," he said.