The LA Innocence Project has taken on Peterson's case, arguing in a filing he may be innocent of the 2004 murders of his wife and unborn son. Dateline producer Susan Leibowitz breaks down their arguments to run new DNA tests on old evidence. In Jacksonville, prosecutors lay out their case against Shanna Gardner, accused of plotting to kill her ex. And KHQ Anchor Hayley Guenthner reports back from a sentencing in Coeur d'Alene, Idaho, where a judge called a former state trooper a "remorseless killer."

More reporting by KHQ's Hayley Guenthner