Idaho police “strongly believe” siblings missing since October are in danger—and blasted the children’s mother and stepfather for refusing to cooperate in the investigation.

The blistering statement this week from Rexburg police is the latest twist in the bizarre mystery swirling around Lori Vallow and Chad Daybell—who married after their previous spouses’ suspicious deaths.

Lori’s 17-year-old daughter Tylee Ryan and her adopted 7-year-old son Joshua “J.J.” Vallow have not been seen for two months—and police said the couple told disturbing lies about the children.

“It is astonishing that rather than work with law enforcement to help us locate her own children, Lori Vallow has chosen instead to leave the state with her new husband,” police said in a statement.

“We publicly call on Lori Vallow/Daybell and Chad Daybell to do the right thing and come forward with the information they have about the location and welfare of Joshua and Tylee. This entire investigation could have been avoided if Lori and Chad had simply been honest with law enforcement.”

Daybell is the author of a series of books aimed at a Mormon audience that focus on near-death experiences and doomsday themes, and he and Vallow were both contributors to an organization that dabbled in the same.

Until last year, Vallow had been happily married to Charles Vallow and “a wonderful, loving, attentive mother” to J.J., who has autism, Charles’ sister, Kay Vallow Woodcock, wrote on Facebook.

“Things started changing over the past 18+ months when Lori began spending all her time with a new religious group, that we refer to as a ‘cult,’” Woodcock wrote. “She eventually deserted my brother & JJ for 2.5 months early this year. Charles did his best to save the marriage, of which she had no interest.”

Then, on July 11, Charles Vallow was fatally shot by Lori’s brother, Alexander Cox, during a domestic disturbance that remains under investigation. Cox died on Dec. 12 of unknown causes. The only other two witnesses were the kids, Woodcock said.

Three months after Charles Vallow was killed, on Oct. 19, Daybell’s wife, Tammy, died at home at the age of 49. Daybell refused to order an autopsy on his wife, and the coroner listed the cause of death as “natural,” but authorities have since exhumed her body for further testing.

Vallow and Daybell got hitched weeks after Tammy’s death. According to police, the couple told witnesses that Tylee had died a year earlier, and Chad told someone Lori had no children.

When relatives asked police to check on the children, Daybell allegedly told officers they were with relatives in Arizona, which turned out to be untrue.

“We strongly believe that Joshua and Tylee’s lives are in danger,” Rexburg police said.

“We know that the children are not with Lori and Chad Daybell and we also have information indicating that Lori knows either the location of the children or what has happened to them. Despite having this knowledge, she has refused to work with law enforcement to help us resolve this matter.”

Brandon Boudreaux, the ex-husband of Lori Vallow’s niece, claims his former wife has also gotten mixed up with the doomsday crew. And he told the Arizona Republic that he thinks a Oct. 2 drive-by shooting that he narrowly escaped is somehow connected.

By his account, someone driving Charles Vallow’s car shot at him, and the bullet barely missed his head. Gilbert, Arizona, police confirmed to The Daily Beast that someone shot at Boudreaux as he returned home and said the investigation is ongoing.

“I just don’t know how people can get so wrapped up that they can end up in this space where these people are. It’s just so radical, so different,” Boudreaux told the Republic.

Last week, an attorney hired by Daybell and Vallow said they had done nothing wrong.

“Chad Daybell was a loving husband and has the support of his children in this matter. Lori (Vallow) 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,” lawyer Sean Bartholick said in a statement.

Rexburg police noted that they had been questioned about why charges have not been filed.

“Our primary concern at this point is simply locating Joshua and Tylee and charging decisions will be made in due course based upon the evidence available,” they said. “If we find that harm was done to these children within our jurisdiction, we will prosecute whoever caused that harm.”