the karmen smith murder was now officially a cold case. away. >> does a case like this haunt a police department? >> absolutely, because these cases go home with you in your mind. >> but for years, doss couldn't do anything about it. and then just by chance he was sent to a dna training seminar in 2008, a random assignment that would change everything. >> back in the mid 90s very, very little at all could be done with the hair except to say the color of the hair. now when there's any tissue from the root on the hair whatsoever, it takes just a minute amount of tissue to come up with a full profile. >> it's called nuclear dna testing and dawes immediately thought of karmen smith. karmen was a strawberry blond and he remembered the short, dark hairs recovered from her body. not hers under layers of bedding. >> i felt it was invaluable evidence if there was enough tissue on that hair that was underneath her sweater. >> doss brought one of those dark hairs to a dna lab in texas and waited. it was almost 15 years after karmen smith's murder whe

this case is about karmen. this case is about nick. >> that's all for this edition of dateline. i'm natalie morales, thank you for watching. >> i'm craig melvin. >> i'm natalie morales. >> and this is "dateline". >> i really want people to not be afraid and here i am an actor and i'm on "dateline" and i'm telling you my darkest secrets because i think it will help someone and it's okay to talk about it. >> an actress finds real life drama when her sister and her sister's husband disappear. >> they said lesley didn't show up for work. >> lesley's life had seemed perfect but maybe that was an illusion. >> she mentioned going underground. >> yes, she did. >> had something driven her to leave town or had something very different happened? >> the dog told you a dead body was in the back of the car? >> correct. >> but with few clues, hollywood would stage a dramatic press conference hoping to flesh out a killer. >> i was just floored by what was happening. >> hello and welcome to "dateline. " aasha davis moved to hollywood with big dreams and her sister lesley followed to support her.