Lori Vallow and her husband, Chad Daybell, have been indicted on murder charges in connection with the deaths of her two children nearly a year after their remains were found on the doomsday author's property, prosecutors said Tuesday.

They both face two counts of first-degree murder, conspiracy to commit first-degree murder and grand theft by deception in the deaths of 17-year-old Tylee Ryan and 7-year-old Joshua "JJ" Vallow. They also face an additional conspiracy to commit first-degree murder charge in the death of Tammy Daybell, Chad Daybell's former wife. 

He is also charged with the first-degree murder of Tammy Daybell and two counts of insurance fraud related to the collection of benefits he allegedly received after her death. Vallow also faces grand theft charges related to Social Security survivor benefits for the children. 

"We know many members of the community may feel that progress on this case has been slow," said Lindsey Blake, Fremont County prosecutor. "Due to the ongoing safety restrictions imposed by the courts during the pandemic, we just recently were given permission to present information to the grand jury for their review."

REMAINS FOUND ON IDAHO PROPERTY ARE LORI VALLOW'S MISSING CHILDREN, FAMILY SAYS; CHAD DAYBELL CHARGED

Prosecutors said Vallow and Daybell each face anywhere from life in prison to the death penalty. They were both served with warrants on Tuesday. Blake did disclose which penalty will be pursued. 

They are scheduled to make a court appearance on the new charges Wednesday morning. Calls to their attorneys were not immediately returned. 

Both were already charged with conspiracy to destroy, alter or conceal evidence in connection with hiding of the children's remains. JJ and Tylee’s bodies were found buried in Daybell’s backyard in Fremont County, Idaho, in June 2020.

They vanished in September 2019 but were never reported missing by their mother. Concerned relatives notified authorities that they had not heard from them, prompting a law enforcement inquiry. 

The couple has pleaded not guilty to the earlier charges. They married weeks after Tammy Daybell died in October 2019. She was initially thought to have died of natural causes but her body was later exhumed in December of that year. 

The results of an autopsy on Tammy Daybell have not been publicly released. 

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Vallow and Daybell fled to Hawaii after authorities began investigating the disappearance of the children. Vallow was later arrested in February on child abandonment charges.

She lived in Arizona prior to moving to Idaho after her former husband, Charles Vallow, was fatally shot in 2019 by her brother, Alex Cox. Cox died of natural causes in December of that year.