Lori Vallow Daybell, the "doomsday mom" who is on trial for the death of her fourth husband, had a tense exchange with the woman who went on a date with him the night before he was murdered.

Lori Vallow Daybell’s brother told jurors at her Arizona trial that he believes his sister was behind the killing of her estranged husband.

Adam Cox, a witness for the prosecution, testified that he had "no doubt" his two siblings conspired to kill Charles Vallow.