>> darren wyatt was promoted to detective sergeant and his case load shifted to other types of crime. but he never forgot his promise to mary, in part, because of a milestone in his own life. >> my first daughter was born and i remember going to mary shortly after that and looking her in the eye and saying i know, i know now how you feel. i know t i can feel it myself. i'm a dad now. and you haven't given up. i won't give up. >> in 2003, nine years after the murder, darren once again approached a friend in the d.a.'s office. >> i said i've got a cold casey need you to take a look at. he physically stops walking and says if it's the case i'm thinking about, i'm not going to touch it. >> darren was persistent. eventually, he persuaded his friend to take cathy's case back to the d.a.'s homicide unit. the same unit that rejected it twice before. this time, though, something