mclelland had to bow out of the investigation.o do what they could. >> anything that anyone can think of there are going to do it. >> marks checks in his personal background don't go anywhere. so they looked in his professional cases, from 30 years ago, to a few weeks ago. >> how did you go from it could be this person? or this? person >> you see if they're locked out up, you see where they are, their whereabouts. there's usually something specific about someone's case that could give them cost to have a grudge. >> four weeks into the investigation, a tip came into the crime stoppers tip line which looked like a big break. >> the tipster said that they had been in a bar in a small town and kaufman and overheard to white men talking about the hasse killing and talking about how they did it. >> so they use the crime stopper system, the tipster remained anonymous, this was gonna be a game-changer. investigators would need more invent mission or luck. >> you're still looking for the big break or lucky traffic stop. someone who knows a