REXBURG, Idaho — Family members of a man and woman at the center of a nationwide search for two missing children in Rexburg, Idaho believe they may be members of religious cult infatuated with the end of the world.

Chad Daybell and Lori Vallow have been on the run, accused of lying about the location of her missing children.

Police across the country are continuing to search for 7-year-old Joshua “JJ” Vallow and 17-year-old Tylee Ryan, who may be in serious danger. Police in Rexburg said they have not been seen since September.

Assistant Chief Gary Hagen of the Rexburg Police Department said Chad Daybell and Lori Vallow repeatedly lied about the location of the missing children before investigators lost contact with the couple.

Brandon Boudreaux, who married into Lori Vallow’s family, said he believes her new religious beliefs have led to the deaths of multiple family members along with the disappearance of her children.

“I spent the last 11 years of my life spending time with Lori and her now-deceased husband Charles,” Boudreaux said. “I don’t know what happened to those kids, but I know there’s people who do, and they’re not talking… I love them both. I hope they’re safe. They’re both just innocent and they didn’t deserve to be involved in any of this.”

Boudreaux said his wife, Lori Vallow’s niece, decided to follow her aunt in joining a “cult” with Chad Daybell, a self-proclaimed Latter-day Saint author known for his religious books detailing the end of the world. The religious group is an offshoot of The Church of Jesus Christ of Latter-day Saints with more radical beliefs.

Lori Vallow sometimes participated in podcasts with Chad Daybell, on the “Preparing a People Podcast Network.”

Many of the podcasts featuring Chad Daybell have been removed from the website.

“You can’t be a member of the church and believe those things,” Boudreaux said. “I think it’s an infatuation with the end of the world and an infatuation with power, and they’re using it to try to make money off of people’s beliefs.”

“Do they consider themselves LDS still?” FOX 13 reporter Adam Herbets asked.

“Unfortunately, I think they do,” Boudreaux said. “It just makes you sad. A lot of people I care about aren’t here anymore because of these ideas.”

Police have confirmed they believe the children’s disappearance may be connected to the death of Chad Daybell’s late wife, Tammy Daybell.

When Tammy Daybell died at the age of 49 in October, doctors at the time said it was from “natural causes.” She was buried in Springville, Utah three days later. Police later determined that her death may have been suspicious and exhumed her remains to conduct an autopsy on Dec. 11.

Tammy Daybell’s father, Ron Douglas, said he saw his daughter about two weeks before her death. He said she was in good health and in good spirits, dancing in the living room.

On October 19, Douglas said he received a call from Chad Daybell “broken-hearted and sobbing,” explaining that his wife went to bed in a coughing fit and never woke up.

“We speculate like everybody else,” Douglas said. “It’s hard to know that we lost our daughter and that our son-in-law of 30 years has stepped into this mess. We don’t know. We’d like to hope for the best. Every time you peel a layer off the onion it makes you scratch your head.”

Douglas said he did not know investigators exhumed his daughter’s body until police told him.

Police said Chad Daybell and Lori Vallow were married within only a couple weeks of Tammy Daybell’s death. Deputies with the Fremont County Sheriff’s Office are now leading the investigation into Tammy Daybell’s death.

“We’re just waiting for the results (of an autopsy),” Douglas said. “We knew nothing about the missing children.”

Lori Vallow is also a recent widow. On July 11 in Chandler, Arizona, her brother Alex Cox shot and killed her husband, Charles Vallow. Cox said he shot his brother-in-law in self-defense. That case was under investigation by the Chandler Police Department and Maricopa County Attorney's Office.

Months later, in December, Alex Cox died. Both Hagen and the Chandler Police Department said they could not comment on the details surrounding his death due to the ongoing investigation.

“Charles was a great dad. He provided well. He worked so hard,” Boudreaux said. “There’s family members in Utah and Idaho and Arizona, and a lot of them are confused.”

According to medical records obtained by FOX 10 Phoenix, Tylee Ryan’s father Joseph Ryan died from a heart attack in 2018. It’s unclear whether his death is related to the current investigation. His body was cremated and cannot be exhumed.

Boudreaux said he did not think it was a coincidence that so many family members have died within such a short amount of time, especially because he accuses his ex-wife of using her family’s newfound religious beliefs to justify trying to kill Boudreaux.

“A couple months ago there was an attempt on my life, so I went into hiding with my kids,” Boudreaux said. “All I could think was, ‘Someone’s shooting at me. What do I need to do? I need to hit the gas and get out of here.’”

Boudreaux declined to comment on the appearance or identity of the suspected shooter due to an ongoing investigation.

“You have no doubt in your mind, Chad and Lori are responsible for the deaths of their spouses?” asked FOX 13 reporter Adam Herbets.

“I’m just a person, so what do I know? But yeah, I mean… I just wonder why you couldn’t just get divorced like normal people and just go be together if that’s what you wanted,” Boudreaux cried. “I don’t know what they’re doing. It doesn’t make any sense… If I could say anything to them, I would just say tell the truth, you know? They’re going to figure it out eventually anyways.”

The Rexburg Police Department said their investigative focus will remain on the children and their newlywed parents, who have never reported the children missing or been cooperative throughout the search.

"We've gotten pretty much the run around from them," Hagen said. "We do know there is some frustration with people thinking that we haven't done this in a timely manner, but there are certain stipulations -- requirements we must meet before we can list a child endangered."

According to EastIdahoNews.com, attorney Sean Bartholick issued the following statement Monday on the Daybells’ behalf:

“Chad Daybell was a loving husband and has the support of his children in this matter. Lori Daybell is a devoted mother and resents assertions to the contrary. We look forward to addressing the allegations once they have moved beyond speculation and rumor.”

Anyone who has seen either child since September is asked to call 208-359-3000 or 1-800-THE-LOST (843-5678). Police added that Joshua may go by the nickname "JJ" and has special needs.