IDAHO FALLS — Dateline NBC will air a two-hour program Friday with new information and interviews in the case of two missing Rexburg children.

Tylee Ryan, 17, and Joshua “JJ” Vallow, 7, have not been seen since September. Their mother, Lori Vallow Daybell, is in the Madison County Jail on two counts of desertion and nonsupport of dependent children. The Idaho Attorney General’s Office is investigating Daybell and her new husband, Chad Daybell, for the death of Tammy Daybell, Chad’s wife who died suddenly in October.

The major players and timeline in the disappearance of JJ Vallow and Tylee Ryan

Dateline aired an episode about the investigation on Feb. 14. Since then, there have been numerous developments and EastIdahoNews.com has been working with NBC producers and correspondent Keith Morrison on the upcoming program.

“It’s a shocking story and a remarkable story,” Morrison tells EastIdahoNews.com. “I’ve seen public interest in cases before but this really is far more than anything I’ve seen in a very long time – since maybe Michael Jackson or OJ Simpson.”

Morrison interviewed several people who are closely tied to Lori and Chad, including Lori’s niece Melani Pawlowski and her new husband Ian. The couple has not spoken publicly about the case but sat down with Dateline for hours and no questions were off the table.

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Melani’s husband, Brandon Boudreaux, was shot at Oct. 2 in Gilbert, Arizona. Investigators believe Lori’s dead brother, Alex Cox, may have been the shooter. After Brandon and Melani divorced, she quickly married Ian and moved to Rexburg.

“Melani essentially appeared to want to present that all is fine,” Morrison says of the interview. “She acted like, ‘I don’t know of any problems whatsoever. We were all just doing our own thing and anything that seemed suspicious was merely a coincidence.’ She’s a sweet, very attractive young woman who looks at you with big eyes and says it’s absolutely the truth. The viewers can look at it and see what they think.”

During the show, Morrison explores Chad and Lori’s religious beliefs, including reports the couple thought JJ and Tylee had become “dark” and were “zombies.” Ian Pawlowski allegedly wrote about the bizarre beliefs the night he married Melani and she explained what Chad and Lori had told her. She also reportedly expressed that Brandon had been possessed by a demon or “another dark entity.”

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“There are all these people who surround Chad and Lori who appear to be part of this group,” Morrison says. “When you hear people talk seriously about evil spirits inhabiting their spouses or members of their family, or people becoming zombies and needing to be eliminated, you’re getting into some serious stuff. And those are the kinds of materials we have found ourselves dealing with over this period of time.”

Watch our interview with Morrison in the video player above to learn more about the program. It will air on KPVI Friday, May 1 at 8 p.m. MST. The episode will be posted online a few days after it premieres on television.