i'm natalie morales. the prosecution made the argument that bob ferrante certainly had the means to kill his wife. now it was the defenses turn and their goal was to dismantle the largely circumstantial case presented. questioning the motive and whether she even died from the poison at all. now with the conclusion of "lethal weapon", here's dennis murphy. >> the commonwealth of pennsylvania had tried to paint robert ferrante as a jealous has been, driven by a reach to poison his wife. how did he do it? prosecutors believed he slipped the cyanide inside a drink and gave it to her shortly after she came home that night. a theory, said judge manning, that was tough to prove. >> no one stood there with their two eyes and said, i saw him put the cyanide in the drink and give it to her. no one said that. >> that is a weak point in the prosecutions argument. >> of course it is. but keep in mind, circumstantial evidence, most