The case involving the death of a man previously married to Lori Vallow, the mother accused of conspiracy with her fifth husband in connection with the deaths of her two children, is under review, authorities said. 

Phoenix police are reviewing an investigation into the April 2018 death of Joseph Ryan, Vallow's third husband, a police spokeswoman told Fox News without elaborating. The couple divorced 14 years prior to his death.

The inquiry comes days after several news outlets published an audio recording released by Ryan's sister, Annie Cushing. In it, Cushing claimed Vallow is heard talking about wanting to kill Ryan. 

LORI VALLOW, CHAD DAYBELL TALKED BY PHONE ON DAY KIDS' BODIES FOUND, RECORDING SHOWS

The recording features a voice, identified as Vallow, telling friends she considered murdering Ryan because of the custody battle over their daughter, 16-year-old Tylee Ryan, who is one of the children found dead earlier this year, according to the Daily Mail

“He was constantly trying to get custody of my 3-year-old daughter,” Vallow allegedly said in the recording. “If he comes against you once, if he comes against you twice, if he comes against you three times then you can kill him, it says it in the scriptures.” 

Cushing said the recording was from October 2018. A medical examiner determined Ryan died from a heart attack. 

Meanwhile, Vallow remains jailed in Idaho along with her fifth husband, Chad Daybell, on conspiracy charges related to allegedly hiding the remains of her children, Ryan and 7-year-old Joshua "JJ" Vallow. The children's bodies were found on Daybell's property in June. 

Neither is charged in the children's deaths. 

Both children vanished in September 2019, but they were never reported missing. Vallow and Daybell are linked to two other deaths, including the death of Daybell's wife, who died weeks before he married Vallow. 

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Vallow's other husband, Charles Vallow, was shot and killed by his brother-in-law, Alex Cox, in July 2019 in a suburban Phoenix home. Cox died of natural causes in December.

Investigators determined he acted in self-defense.