Prosecutors said during the Lori Vallow murder trial on Monday that her husband’s ex-wife, Tammy Daybell, died of asphyxiation.

Vallow is charged with murder, conspiracy to commit murder and grand theft in connection to the deaths of her two children, Joshua “JJ” Vallow and Tylee Ryan, and Tammy Daybell. She has plead not guilty and her trial started on April 3.

Tammy Daybell, the ex-wife of Chad Daybell, was found dead in October 2019 of what were believed to be natural causes at the time. Investigators later exhumed her body and conducted an autopsy, which ruled her death was a homicide.

Fremont County Prosecutor Lindsey A. Blake revealed the results of the autopsy during opening arguments of the trial on Monday morning, according to NBC News affiliate KSL-TV. Tammy was married to Chad Daybell for 28 years before her death.

Chad Daybell is charged with murder in the death of his ex-wife, and accused of committing insurance fraud related to her death. 

Tammy Daybell’s death came just a few months after that of Charles Vallow, Lori Vallow’s ex-husband, who was shot and killed by her brother, Alex Cox. A grand jury charged Lori with conspiracy to commit murder in the first degree nearly two years after his death, the Maricopa County Attorney’s Office said. She will be tried separately, in Arizona, in that case. Cox died in 2019 and was never charged. 

Vallow and Chad Daybell married just two weeks after Tammy Daybell’s funeral, KSL-TV reported. Police documents obtained by KSL revealed that Charles Vallow had learned of Lori Vallow’s infidelity with Chad Daybell 12 days before he died and threatened to tell Tammy Daybell. 

Prosecutors believe Vallow and Chad Daybell became obsessed with doomsday-focused religious beliefs that led them to commit a series of four murders: those of Vallow’s children and each of their former spouses.

Vallow’s trial comes years after the disappearance of her children, Joshua and Tylee, made headlines, as the indictment against her and Chad Daybell took months of investigative work and Vallow’s mental competency was questioned. 

Vallow has pleaded not guilty to charges of murder, conspiracy and grand theft in the deaths of Joshua and Tylee, who were 7 and 16 when they disappeared in September 2019. Their disappearance sparked a monthslong search, and police eventually found their remains on property in rural Idaho belonging to Chad Daybell. 

Police uncovered the remains in June 2020 after they searched the property in Fremont County. Chad Daybell was arrested on charges of destruction, alteration or concealment of evidence, as well as desertion.

Days later, police confirmed that the bodies were identified as those of Joshua and Tylee. 

Court documents later revealed that Joshua’s remains had been buried in a pet cemetery and that Tylee had been dismembered and burned in a fire pit. 

Vallow and Chad Daybell weren’t indicted on murder charges until May 2021.

During opening statements on Monday, Fremont County Prosecutor Lindsey A.Blake said what was left of Tylee’s remains were a mass of tissue and bone and JJ’s body was duct taped in garbage bags, KTVB reported.

It was decided in a hearing last month that Vallow will not face the death penalty if convicted.