“Doomsday cult” mom Lori Vallow Daybell was sentenced Monday to life in prison without the possibility of parole for killing her two children, and for conspiring in their murders and that of her husband’s previous wife.

On May 12, a 12-person Idaho jury found Vallow Daybell guilty of murdering her 16-year-old daughter, Tylee Ryan, and her 7-year-old son, Joshua “J.J.” Vallow, as well as conspiring to kill the children and her husband’s former wife, Tammy Daybell, and grand theft by deception. 

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Idaho Judge Steven Boyce said in court Monday that Vallow Daybell had committed an “unimaginable” crime in killing her kids, according to ABC News.

Prosecutors had argued she killed her children because she believed they had turned into zombies.

J.J. Vallow’s biological grandmother, Kay Woodcock, spoke of her grandson’s death in court Monday, calling Vallow Daybell’s deeds “acts of depravity, cruelty and betrayal” that “have no limits.”

The siblings vanished in 2019, before their bodies were recovered in the backyard of Vallow Daybell’s husband, Chad Daybell, in 2020.

Vallow Daybell’s attorney John Thomas pleaded to the court Monday to show mercy on Vallow Daybell.

“Lori, if she could speak to each one of those people who have been hurt by this case… her message would be one of love,” Thomas said.

RELATED: J.J. Vallow’s Grandparents Applaud Idaho ‘Doomsday Cult’ Mom Lori Vallow Daybell’s Murder Convictions

When Vallow Daybell spoke during Monday’s sentencing hearing, she quoted Bible verses and told the court, “Jesus Christ knows the truth of what happened here. … No one was murdered in this case. Accidental deaths happen. Suicides happen. Fatal side effects from medications happen.”

She also said she has communicated with her children in heaven, claiming they are “happy and busy in the spirit world.”

“Because of my communication with my friend Tammy Daybell, I know she is also very happy and extremely busy,” she added.

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Noting Vallow Daybell’s mental health issues and her denial in court Monday of committing the murders, Boyce sentenced her to serve three consecutive terms of life in prison without parole.

Before handing down the sentencing, Boyce expressed that a mother killing her children is the most “unimaginable type of murder,” adding that the woman seemed to show no remorse for her actions.

“You had so many other options. … You could have found someone to take care of those kids,” he said. “You killed those children … to remove them as obstacles and to profit financially.”

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Prosecutors read a statement in court Monday from Vallow Daybell’s surviving son, Colby Ryan, in which he remembered his late brother and sister.

“Tylee and J.J. brought so much light into this world,” Ryan stated. “I pray for healing for everyone involved, including those who took the lives of all the ones we loved.”

Larry Woodcock, J.J. Vallow’s grandfather, said in a May news briefing after Vallow Daybell’s conviction, “I want to personally thank and I want to personally hug every one of those jurors.”

Larry also mentioned Tammy Daybell at the time, who was initially believed to have died of natural causes in her sleep, before an autopsy later confirmed she died of asphyxiation in April of 2019.

“Tammy, I never met you,” Woodcock said. “You are a part of our life. Tammy I am sorry [for] what happened to you.”

RELATED: ‘Doomsday Cult’ Mom Lori Vallow Daybell Found Guilty of Murdering Children, Conspiring To Kill Lover’s Wife

Chad Daybell, 54, who is being tried separately next April, pleaded not guilty to charges in connection with the murder of his first wife, Tammy, as well as for the deaths of J.J. and Tylee. He was also charged with conspiracy to commit the murders of all three victims.

Vallow Daybell is also facing conspiracy to commit murder charges in Arizona for the death of her fourth husband, Charles Vallow, as well as the attempted killing of her former nephew-in-law, Brandon Boudreaux.

Alex Cox, the doomsday cult mom’s late brother, allegedly opened fire on Bordeaux, the ex-husband of Vallow Daybell’s niece, Melani Pawlowski, on October 2, 2019, after she and Cox decided that, “at least one of them or another would engage in conduct constituting the offense of first-degree premeditated murder,” prosecutors say. Bordeuax survived the incident.