Lori Vallow murder trial day 17: Tammy Daybell's sister testifies, DNA found on pickaxe

It's day 17 of the Lori Vallow murder trial in Idaho and there was more graphic evidence for the jury. The so-called "Doomsday Mom" who prosecutors say used her religious beliefs to justify murdering her two children was back in court April 27.

The day was mainly about the forensics. Witnesses representing the FBI and the Idaho State Police took the stand and again, we want to warn you that some of the details are graphic.

The prosecution called on the sister of Tammy Daybell. Tammy was married to Chad Daybell for nearly 30 years after meeting at BYU when Daybell was a grave digger. Investigators say Daybell and Lori Vallow conspired in the murder of Tammy in October 2019, and then they married weeks later.

Samantha Gwilliam told the jury how she found out about her sister's death. She says Chad called her, saying Tammy had been coughing all night and was dead the next morning. But Tammy's official cause of death was asphyxiation.

"Did Tammy ever indicate to you that she had suspicion that Chad was having an affair?"

"No, she never said anything about it. If she did have any inkling, I think he probably brushed it away," Samantha answered.

We also learned that Idaho State Police found latent prints on black plastic that JJ Vallow was wrapped in, matching Alex Cox. Alex was JJ's uncle and Lori's brother, who is now dead. He's also the person JJ was last seen with on the night of September 22, 2019, holding the 7-year-old boy in his arms.

By June 2020, JJ and his sister Tylee Ryan, were found dead in Chad Daybell's backyard.

Dr. Angi Christensen, an FBI forensic anthropologist, testified, saying she tested 18 hand tools recovered from Daybell's property. She told the court she found several blood stains and what appeared to be charred flesh on the tools.

DNA testing done on a shovel and the handle of a pickaxe matched Tylee's DNA. A CT scan was performed on Tylee's skeletal remains and Christensen testified about the trauma found on specific bones.

Tammy Daybell's sister will continue her testimony on April 28. The jury has taken in a lot of testimony and evidence with about 15 witnesses taking the stand so far this week.

The court will adjourn a couple of hours earlier on Friday.

For all previous and extensive coverage on this case, visit https://fox10phoenix.com/vallow + watch the in-depth special here.