welcome back to dateline. i m andrea canning. helene prusiensky was found murdered in a feel outside of denver. president least pursued every lead, including what turned out to be false confessions from two notorious serial killers. but the investigation stalled. decades went paths before a tireless young detective picked up the case and set her sights on a promising new suspect. back to josh mankiewicz with a promise to clean. helene prusiensky s murder had become a textbook example of a cold case. but in 1998, a rate of hope spring up. it came from a somewhat newer textbook. the use of dna evidence had become a revolutionary tool in criminal investigations. and douglas county detectives realize there was dna from