(NewsNation) — Lori Vallow, the Idaho mother accused in the triple murder of her two youngest children as well as her new husband’s previous wife, was willing to “remove any obstacle in her way to get what she wants,” a prosecutor told jurors Monday morning.

“The defendant used money, power and sex to get what she wanted,” Fremont County Prosecutor Lindsey Black said. “It didn’t matter what it was.”

It’s a case that has garnered national attention, in part because of the severity of the crimes Vallow is accused of, and also because of the the unusual doomsday-focused religious beliefs involving “dark spirits” and “zombies” she and her husband, Chad Daybell, reportedly share.

Vallow and Daybell are charged with multiple counts of conspiracy, murder and grand theft in connection with the deaths of her two youngest children: 7-year-old Joshua “JJ” Vallow and big sister Tylee Ryan, who was last seen days before she turned 17.

Authorities started investigating Lori Vallow and Chad Daybell in November 2019 after family members reported the children were missing. The children’s bodies, after months of searching, were found buried on Daybell’s rural Idaho property.

“Charred remains, that’s what was left of Tylee,” the prosecutor said, showing jurors a photo of human remains partially uncovered in a patch of dirt. “You will hear it explained as a mass of bone and tissue. That’s what was left of this beautiful young woman.”

JJ’s body was wrapped in trash bags and duct tape, Blake said — the tape binding his arms in front of him and wrapping around his head.

Prosecutors have also charged Daybell and Vallow in connection to the 2019 death of his previous wife Tammy.

Both Vallow and Daybell have pleaded not guilty. The two will be tried separately.

The kids and Daybell’s previous wife Tammy Daybell were all killed because they stood in the way of the couple’s relationship, Blake said.

The couple were married two weeks before Tammy Daybell died of what were initially reported as natural causes. However, investigators later had her body exhumed after suspicions arose.

Prosecutors say Daybell and Vallow espoused strange doomsday-focused beliefs to further their alleged plan to kill the kids and Tammy Daybell to collect life insurance money and the children’s Social Security and survivor benefits.

Defense attorney Jim Archibald presented jurors with a far different picture, describing Vallow Daybell as a “kind and loving mother to her children” who happened to have a particular interest in religion and Biblical prophesies involving the end of the world.

“Some people care less about Biblical prophesies, some people care a lot about it,” Archibald said. “Thankfully in this country, we get to worship as we choose.”

Vallow Daybell is presumed innocent, Archibald reminded jurors, and said the criminal charges themselves — which accuse Vallow Daybell of either directing, encouraging, assisting or participating in the murders — show that prosecutors don’t really know what happened in the case.

Archibald also said Vallow Daybell’s religious beliefs only began to change after she met Chad Daybell, a religious author whose fictional books focused on the apocalypse and were loosely based on the beliefs of The Church of Jesus Christ of Latter-day Saints.

But Blake said those beliefs veered toward the extreme, with the couple saying people were “dark” or “light,” telling friends and acquaintances that “dark” people had been taken over by evil spirits. They eventually began teaching friends that once those evil spirits were strong enough, the person became a “zombie,” and the only way to free that person’s soul was by killing them.

Jury selection took place last week. Eighteen-hundred people were called as potential jurors. Ultimately, 10 men and eight women were selected.

NewsNation legal contributor Jesse Weber said opening statements are significant since it’s the first step for both the defense and prosecution to lay the groundwork for the trial.

“If you put yourself in the minds of the jury, this is the first time they hear about the case. It gives the opportunity for both sides to present their story, their version of what happened,” Weber said.

Vallow is facing life in prison if convicted, but not the death penalty. East Idaho News previously reported that District Judge Steven Boyce ruled to dismiss the death penalty as an option “to ensure the rights of the defendant to a fair trial are protected.” Currently, Vallow is being housed at the Ada County Jail in Boise, Idaho.

Criminal defense attorney Jonna Spilbor said this case is “far from a slam dunk” for the prosecution and defense.

While the prosecution has a tragedy it can point to, beyond that, “they don’t have a lot of direct evidence,” Spilbor said on “NewsNation Live.”

“They don’t have a cause of death. They don’t have a murder weapon,” she said. “I think the prosecution is going to have to focus on the odd doomsday cult relationship that Lori (Vallow) Daybell shared with her husband and many other people in her life.”

On the defense side, Spilbor said, they have to answer the question of why Vallow didn’t react differently when her children first went missing.

JJ Vallow’s grandmother, Kay Woodcock, was the first witness to take the stand after opening arguments. She cried after Madison County prosecutor Rob Wood showed her a photo of JJ taken when he was around 5 or 6 years old, sitting in a vehicle wearing a seatbelt.

“That is my beautiful grandson, JJ,” she said.

Woodcock said Vallow Daybell was once a “doting mother,” but her opinion of the defendant changed after Charles Vallow filed for divorce in early 2019. After Charles Vallow died, once-regular phone calls and visits with JJ dropped off, she said.

She only had contact with JJ three times after his father died, Woodcock said, in short FaceTime video calls. The last call happened the month before JJ was last seen alive, she said. It only was about 35 seconds long.

“He just said, ‘Hi Mama, hi Papa,’” Woodcock said, referring to JJ’s nicknames for his grandparents. “’Gotta go, Mama. Gotta go, Papa. Bye!’”

Woodcock eventually contacted law enforcement agencies and asked them to do a welfare check on JJ. When police couldn’t find either of the kids, they opened a missing persons case.

Rexburg Police started investigating in November 2019. During that period, police say the couple lied about the children’s whereabouts.

Prosecutors say the couple planned to use life insurance money from Tammy Daybell’s death, and that Vallow Daybell kept collecting and spending the children’s social security and survivor benefits after they died.

NewsNation digital producers Cassie Buchman and Caitlyn Shelton contributed to this report.