Dramatic closings in the tech exec trial. Debate over DNA analysis in a quadruple homicide. And Dennis Murphy on Amanda Knox.

Listen to this week's episode of the Dateline: True Crime Weekly podcast with Andrea Canning. A jury in San Francisco begins deliberations in the trial of the accused killer of the Cash App co-founder. And in suburban New Jersey, science takes center stage in the courtroom ahead of the trial of a man accused of killing his own brother and his brother's family. Plus, 15 years after the trial of Amanda Knox, Dennis Murphy reflects on the case.