Lori Vallow Daybell stood still and didn't even flinch as a judge read the verdict saying she has been found guilty in the murders of her two youngest children and her husband's ex-wife.
She appeared in court in a simple black dress and remained expressionless the whole time, in a scene that an expert on her case found made her look "heartless".
John Glatt, who researched the case in depth before publishing his true crime book "The Doomsday Mother", told Mirror Online: "[Her reaction] showed she is completely heartless."
Some individuals in the courtroom gallery wiped away tears, but not Vallow Daybell, who stood like a statue in a chilling emotionless reaction.
Mr Glatt added: "She stood there with a blunt expression. There's obviously something missing from her, she's a heartless person."
This verdict brings an end to a three-year investigation that included strange claims of zombie children, doomsday predictions, and extramarital affairs.
Asked what he thinks about the verdict, Mr Glatt said: "I have been following the case for the last three years and I am delighted that justice has been served for JJ and Tylee and Tammy and Lori has been found guilty for what she has done."
The prosecutors characterized Vallow Daybell as a power-hungry manipulator who killed her children for financial gain, while the defence team argued that she was a protective mother who fell under the romantic influence of cult leader Chad Daybell.
Vallow Daybell was convicted of conspiring to commit the murders of 7-year-old Joshua “JJ” Vallow, 16-year-old Tylee Ryan, and Tammy Daybell.
She was also convicted of grand theft as well as first-degree murder of the two children, a charge that indicates a more direct role in the crimes.
Vallow Daybell's fifth husband, Chad Daybell, faces the same charges, but his trial is still months away.
Prosecutors say the two worked with Vallow Daybell’s brother, Alex Cox, to carry out the crimes. Cox died in December 2019 and was never charged.
Vallow Daybell faces up to life in prison at sentencing, which a judge said would be in at least three months.
Prosecutors said they were not able to comment on the verdict because of pending charges against Chad Daybell. In a statement, they thanked jurors for their service and said they “remain committed to pursuing justice for Tylee Ryan, JJ Vallow and Tammy Daybell.”
Vallow Daybell wanted the victims' money, so she used sex and power to manipulate her brother and her lover into carrying out the crimes, Madison County Prosecutor Rob Wood told jurors during closing arguments.
“Money, power and sex,” Wood said, reprising the arguments his team made at the start of the trial. He claimed Vallow Daybell considered the three victims nothing more than obstacles to her goals.
“What does justice for these victims require? It requires a conviction on each and every count,” Wood said.
The Doomsday Mother, written by John Glatt and published by Mirror Books, is on sale now!
