so, it s obviously an uphill battle when you are working one. reporter: uphill battle does not begin to describe it, the cold case file that he he opened would lead him on the chase of a lifetime and shake the foundations of the l.a.p.d. it dates back to 1986 and to a battle for the truth by the parents of a young bride. you miss her every day. reporter: those parents are nells and loretta rassmussen. there s a pain that is always there that there s no cure for. reporter: who would want to kill sherry rassmussen? she was hard working caring and popular with her co-workers. trained as a nurse, she was director of critical care at a large hospital. we are implementing the people difference program. it was a devastating day. she was 29 years old and just in
woman s name to her parents. instead, she told them not to worry. she told me, i want to see if i cannot work this out myself. reporter: that kwfrconversat happened in a dinner celebrating her 29th birthday. as she had walked away, she turned and gave me a big smile. and i have relived that smile for years. reporter: less than three weeks later, sherry rassmussen lay dead. the rassmussen s insist early in the investigation they told the lead l.a.p.d. detective about sherry s troubling encounters with john s ex-girlfriend. i told the detective, not once, but probably 15-20 times. and he said, the trouble with you is you have been watching too much tv. coming up, old he was offers new clues. the suspect made it appear to