detective kroenke retired. but remember that fresh set of eyes he was hoping for?about archie mcfarland. >> and as soon as i looked at it, i said hey, this guy's good for this murder. >> just what police thought back in the beginning, of course. the difference was, where some das avoid circumstantial cases, lewin, by the way served as an nbc news consultant on other stories, loves them, especially the wriggles of cases gone cold. lewin called a regular partner, veteran detective jim wallace. >> in almost every case there's somebody you could do, if nothing else there's an opportunity for to you look at the evidence anew and if you see anything that was missed. >> so wallace and lewin began by digging into that love triangle, by re-interviewing mary ann, asking about her relationship with both archie and janos, and about the events that preceded the murder. >> typically, when these murders occur, behaviors start slowly kind of fall apart and you see the behavior of the murderer become more and more aggressive and then the murder occurs been. >> and so to the beginni