>> reporter: adkin's defense attorney neil mcelroy couldn't agree more. >> my first instinct when i got the case was, "it's a 1982 case, there must've been a dna hit. something has been discovered, some dna match." and of course, there was nothing. >> reporter: a point he emphasized in his opening argument at russell adkins' trial. >> law enforcement lost or destroyed several pieces of evidence. >> reporter: neil mcelroy and his partner, ronnie wingate, drilled into the prosecution witnesses, challenging their 30-year-old memories. >> but you didn't remember where it was found? >> no, i couldn't tell you the exact spot. >> i don't remember. i mean it was 30-some years ago. >> reporter: as for the original detective, bob bratton? the defense got him to concede just how much evidence was missing. >> as it relates to the clothes, the pool cue, any photos, the map of the scene that was made that night, all that information