welcome to dateline. down on their luck california couple bound up making a fortune in gold. golden not by them happiness. in fact, it just might have been a motive for murder. here is josh mankiewicz. take a look at this security video, and tell me what you see. a woman walks alone to her car in a parking garage in century city, california. is she in danger? same building complex, different angle. a man focuses on his cellphone. oblivious to those around him. who is he calling? you are, in fact, watching scenes from a marriage, the final scenes, as it turns out. the woman is