The sect broke away from the mainstream Mormon Church when it banned polygamy in 1890. It practices plural marriage, a spiritual ritual that is arranged by the group’s prophet through what the church teaches are revelations from God. Members believe that having multiple wives gives them access to the highest level in heaven, the Celestial Kingdom.

In 2004, the sect claimed a membership of 10,000 to 12,000, most living in the twin cities of Hildale, Utah, and Colorado City, Ariz. In an interview that year with The Washington Post, Rodney Parker, the lawyer who spoke for FLDS, and the sect’s self-proclaimed prophet, Warren Jeffs, said the group was looking for an “outpost and retreat” in Texas for 500 church members. They said the sect’s members wanted “to concentrate and focus on their religious mission without the interferences and pressures they’ve been subjected to” in Arizona and Utah.

Now the compound, known as the Yearning for Zion Ranch and strictly off-limits to outsiders, is the focus of a major investigation and intense attention in Texas, too.

The teenager’s calls went to a local family violence shelter, and workers there called a child abuse hotline run by Family and Protective Services. From that tip, investigators began looking into the case last week, and first sought entry into the compound on Thursday, said Darrell Azar, the state spokesman for Family and Protective Services. The first 18 children were removed Friday and the last 15 on Monday night.

They have all been taken to Fort Concho in San Angelo, where authorities are determining what to do with them.