just they ve never been found. so there are missing timecards. exactly two. reporter: would michelle have had those with her that morning cause she was coming in to do payroll? she may have gathered em up. she may have. reporter: and heck emphasized a screwdriver was found in david dooley s locked janitors closet a screwdriver the same size and with similar markings as the pry marks on michelle mockbee s office. what are the odds that in this situation this screwdriver, is a different screwdriver? reporter: the screwdriver, like much of the case, was circumstantial. heck s response, there was simply too much circumstantial evidence to ignore. at some point, a coincidence is not a coincidence. at some point it s just overwhelming evidence of guilt. reporter: now, after years of waiting for their second chance at a trial david dooley s
he had a little bit of closure. and then the second trial comes and everything s just wiped back out. reporter: while michelle s family was bracing for another trial, a lot had changed. prosecutor linda tally smith had lost her re-election bid, and was now a potential witness. so the kentucky attorney general s office, and assistant a.g. jon heck, took over the case. ladies and gentlemen of the jury with every case that i take, i review it, and i ask myself, is this person beyond all doubt guilty? whoever did this was familiar with that facility. then you say, well, who was there? and then whoever did it had to have left. who left? now we re down to one person. reporter: as for the video that showed the unidentified man approaching the warehouse s side door? heck offered an explanation for why the so-called random dude didn t matter. knowing that this is what got