The brutal killing of nine members of a family in northern Mexico highlights the long history of American religious settlers in the region.

The LeBaron family has lived in the turbulent border region for decades, part of a wave of settlers who moved to Mexico in the early 20th century seeking at the time to practice polygamy, which was forbidden by the Church of Jesus Christ of Latter-day Saints. Today polygamy has largely faded from the community.

Long unaffiliated with the mainstream church, fundamentalist Mormon communities in northern Mexico originated in the late 1880s, when a number of families moved to the states of Chihuahua and Sonora.

Religious communities that date themselves to Joseph Smith, founder of the Church of Jesus Christ of Latter-day Saints, often call themselves Mormon. The mainstream church has abandoned the moniker.

After the United States criminalized polygamy in 1882, the leader of the church at the time, John Taylor, encouraged some members to settle in northern Mexico as a way to escape federal prosecution.

“They were seen as colonies of refuge,” said W. Paul Reeve, a professor of Mormon studies at the University of Utah. “The Mexican government said they would look the other way regarding polygamy; they were desirous to have people settle their northern frontier.”

The church formally abandoned polygamy in 1904 and announced that anyone who practiced polygamy would be excommunicated. Some families continued the practice and established their own splinter churches or communities.

Though some of these families’ descendants moved back to the United States during the Mexican Revolution, many remained, prospering as farmers and ranchers.