here's josh mankiewicz with "the smoking gun. >> february 2nd, 2009, homicide detective arrives before los angeles police department's van nuys station. >> i was tired >> reporter: had nht before, and beer flowed freely. >> seemed to be good way to spend the day, cup of coffee and caught up on reading. >> reporter: cup of aspirin. >> maybe >> reporter: reached for a file sitting on his desk for months, murder of sheri rasmussen. shot to death in her condo, a few miles from where nuttal worked just as troubling, murdered a generation ago, february 1996. meaning the odds of catching her killer were slim to none >> memories fade, evidence has to be relocated, so it's obviously uphill battle, what you're working with. >> reporter: doesn't begin to describe it. cold case file that he opened that bleary eyed monday morning would lead him on chase of a lifetime and shake the foundations of the lapd. dates back to 1986 and battle for truth by parents of a young bride. >> we miss her every day. >> nils and loretta rasmussen. >> doesn't make a difference what day it is, it's a pain always there,

police rounded up several potential suspects but here's josh mankiewicz with under a halloween moon. >> it's the one time when everyone pretends to be someone else. when being two-faced is part of the deal. >> there's a feeling that maybe the rules don't apply. and that during those moonlit hours, we all have license to eat, drink and be scary. >> halloween morphed from our national sugar -- to alan alcohol party. nowhere is that more true than in north dakota. several lives would collide under that halloween moon. at least one person may have used a costume to try and hide his true identity, a murderer. that weekend before halloween here in grand forks, heather eastling and her boyfriend, joel lovelien, were putting on costumes getting ready to go out. >> night with friend. >> he's dressed up as a hockey fan wearing his favorite green jersey. >> dressed in a mechanic's outfit. a friend of mine texted me and said meet us at the broken drum. >> half casino, half bar. heather and joel had a lot to celebrate. she had just moved here from texas after dating long distance. it was nearly l

here's josh mankiewicz with "deadly detour." >> all they wanted was to get home. turning off the interstate. to escape the crawling atlanta traffic. >> he says, girls, this is the wrong place, we don't need to be here, this was a bad idea. >> it's still hard to math tom fathom what happened next or why. >> i was trying to figure out where the explosion was. >> but here's what's pretty clear. one wrong turn really can destroy your life. >> to think that one moment in time you have an accident and you lose everything after that. >> our story begins and ends with her, diane mciver. nobody knows her better than dani jo. >> she's beautiful, she's funny, she was brilliant. she was driven. >> diane was born in auburn, alabama, where she survived a sad and difficult childhood. she realized her dreams in atlanta, a place that matched her ambition. >> what was she looking for? >> she was looking for success. >> diane was barely out of high school when she went to work at u.s. enterprises, a company in atlanta. she was a bookkeeper, but soon caught the eye of her boss, billy