Dec. 7 (UPI) -- Convicted Idaho murderer Lori Vallow Daybell was arraigned Thursday in Arizona in connection with the 2019 death of her fourth husband Charles Vallow.
Daybell, who was convicted earlier this year for the deaths of her children Joshua "JJ" Vallow and Tylee Ryan, was extradited to Arizona to face new murder charges.
Prosecutors said they believe Daybell plotted with brother Alex Cox to kill Vallow four years ago. Cox shot and killed Charles Vallow at the couple's home in July 2019 in what Cox said was self-defense. Cox died several months later from natural causes.
Authorities call the Daybell case "complex" and "difficult."
In July, an Idaho judge sentenced Daybell to life in prison without parole after being found guilty of murdering her two children as part of what prosecutors called a "doomsday cult." A jury had found her guilty of the murders on May 12.
Daybell's fifth husband, Chad Daybell, has also been charged with the children's murders but has yet to face trial.
Daybell has also been implicated in the shooting of her niece's ex-husband Brandon Boudreaux. Boudreaux told police he was shot at three months after Charles Vallow's death outside his home in Gilbert, Ariz. He told police Cox was behind the wheel of the vehicle the shots came from.
A Maricopa County Attorney's Office indictment later accused Daybell and Cox of plotting to kill Boudreaux, but that case remains pending.