A third man has been charged with child sexual abuse in connection with a Utah doomsday group that believed in polygamy and took child brides.

Robert Shane Roe, 34, of Castro, California, met the two founders of the group in a Facebook discussion group last year and traveled out to Utah where he was given a "bride" — a 5-year-old girl related to one of the men, prosecutor Kevin Daniels said.

Investigators knew previously that Roe was involved in the group, but the girl only recently revealed what happened when she was alone with him, said Daniels, the Sanpete County Attorney in central Utah.

Roe was charged Thursday with sodomy of a child for the alleged activity in August 2017. No attorney is listed in court documents for Roe.

Daniels said Roe acknowledges being alone with the girl, but denies abusing her.

She is the third girl victimized by men in the group, Daniels said.

The group's two founders — Samuel W. Shaffer, 34, and John Coltharp, 34 — formed a group called the Knights of the Crystal Blade based on arcane Mormon ideas long abandoned by the mainstream church.

Each man secretly married two girls, ages 4 through 8, prosecutors have said. Each man married a relative of the other, according to court documents.

Shaffer was sentenced last month to up to life in prison after pleading guilty to child rape and abuse charges.

Coltharp has pleaded not guilty to sodomy and child bigamy charges. He's scheduled to be back in court Wednesday in Manti, Utah.

The two men were charged after sheriff's deputies descended on a makeshift compound made out of shipping containers in the southern Utah desert about 275 miles (440 kilometers) south of Salt Lake City. Police arrived with helicopters and dogs in December, after the mother of two of the girls reported them missing, along with two of her sons.

The men had taken the children there months before in preparation for an apocalypse or in hopes of gaining followers, authorities said.

The boys were found in the makeshift compound, but it took police another day to find the girls in the barrels and trailer.

Shaffer said at his sentencing that he put the girls in the containers to protect them from the winter weather, and he was glad that the girl spoke out.

Before their arrests, Shaffer and Coltharp met in a Facebook discussion group relating to the 1890 decision to abandon polygamy by the mainstream Mormon church, The Church of Jesus Christ of Latter-day Saints, Daniels said.

Some fundamentalist Mormons believe that decision took the religion too far from its original beliefs.

When Roe visited Utah, he was baptized into the group and bestowed the girl as a "spiritual wife," Daniels said.

Though the group espoused polygamous intentions, none of the men had multiple adult wives, he said. The group also believed that Chinese and Muslim people were planning to come to take over the United States, Daniels said.

Two other followers who are cooperating with investigators could be charged at a later date with obstruction of justice, but they aren't suspected of committing any sexual crimes, he said.

Daniels called Shaffer, Coltharp and Roe "pedophiles cloaking themselves in the robes of religious freedom."

Judge Matthew Bell said his conduct toward the children was "highly disturbing."