MANTI — An alleged leader of a purported doomsday cult out of southern Utah pleaded guilty to charges of child sodomy and child bigamy Wednesday.

John Coltharp, 34, of Spring City, pleaded guilty in 6th District Court to one count of child sodomy, a first-degree felony, and one count of child bigamy, a second-degree felony.

"The fact is I did act contrary to both of those statutes with which I am charged for violating. So yes, I'm guilty of violating both of those," Coltharp said during court proceedings Wednesday.

The group, identified as the Knights of the Crystal Blade, was allegedly led by Samuel Warren Shaffer, 34, of Cedar City, and Coltharp. Coltharp's ex-wife described Shaffer as a "doomsday prepper who believes that the world will soon come to an end."

In September, Shaffer and Coltharp disappeared with their children, allegedly taking each other's daughters as underage brides, according to investigators. After an Amber Alert was issued in December, Coltharp's daughters, ages 5 and 7, and Shaffer's daughters, ages 4 and 8, were found in freezing temperatures, hidden in plastic barrels or in an abandoned mobile home in a remote area of Iron County.

After Coltharp's hearing, Sanpete County Attorney Kevin Daniels said, "As I delved deeper and deeper into the case, this all started … on the internet."

Daniels described the Knights of the Crystal Blade as a "fundamentalist group for Millennials."

The county attorney visited the victims' family in Colorado the previous week, he said, and they told him "what justice would look like" to them.

"We were able to obtain that for them. So for me personally, I'm very happy. The family is relieved. There are still more steps to obtaining full justice, I believe. And a lot of healing that needs to take place over a long time for those children and their family," Daniels said during the hearing.

Daniels said he believes part of the reason Coltharp accepted the deal was that he felt the need to accept personal responsibility for his actions.

"That's only a small slice of solace for me, given what he did," Daniels said. He said Coltharp also "did consider not putting his children and the other children through the rigors of testifying."

According to Daniels, Coltharp gave him the impression that "this was all part of his religious experience. … I think he feels perhaps akin to some of the Biblical prophets that were imprisoned for long periods of time. And so it's hard to get into his head to specifically know why," he said.

Coltharp is scheduled to be sentenced Aug. 8. He faces potential prison sentences of at least 25 years and up to life in prison for the child sodomy charge and one to 15 years for the child bigamy charge.

The plea deal resolves two separate cases filed against Coltharp in Sanpete County. In exchange for the plea, additional charges were dismissed.

Robert Shane Roe, 34, of Castro, California, a follower of the purported doomsday cult, faces a child sodomy charge as well. Roe has contacted prosecutors and "indicates a desire to come to Utah and face the charges," Daniels said. A initial hearing has not yet been scheduled for Roe.

Shaffer has been sentenced to at least 26 years and up to life in prison for rape of a child in a case filed in Iron County. Although Daniels said he had agreed to testify in Coltharp's case, Shaffer still faces additional charges in Sanpete County, where his next hearing is scheduled for June 27.