<p>Prosecutors bring cause of death for JJ, Tylee, and Tammy to the forefront of the trial. A lack of trust in Lori is revealed when jurors hear emotional testimony from Summer Shiflet, Lori Vallow Daybell’s sister. Tammy Daybell’s sister also speaks. CBS News National Correspondent Jonathan Vigliotti and 48 Hours producer Richie Fetzer bring you back inside the courtroom for week four of the trial.</p>