then, at last, it was time for the state's star witness, rachel mcfarland -- the other woman -- to show up and tell her story. did you need the jury to like her? >> we needed the jury to believe her. >> reporter: rachel testified her relationship with seth 2011, which was two months after seth got married. >> it became more sexual, asking me to send pictures. or, i don't know just showing off my body i guess. >> reporter: on may 20th, 2012, preserve, where they took this together. >> i mean he kissed me, touched me. he said that we had everything in common and that he had tried working things out with lisa and things weren't working and i was exactly what he wanted. >> reporter: she said seth repeatedly told her he was going to divorce his wife. >> did he say he loved you? >> yes. >> reporter: but rachel was hedging her bets. she told seth she was also interested in a co-worker named brandon, who just happened to call her during her tryst with seth in the park. >> he just started getting really jealous. >> and so on the 20th when he learned that you were communicating with brandon, he s

rachel, offered as seth's motive for murder in earlier trials, >> good afternoon, miss mcfarland. >> hi. >> reporter: in cross-examination, rachel was on the stand for a scant seven minutes. tick tock, there's the message on thursday. mr. and mrs. resuscitator, blue skies ahead. we're a couple. what do you do with something like that? >> i tried to be as straightforward as i could with the jury. who in the world is going to murder their wife to facilitate a relationship that hasn't even turned sexual? >> you're not having any sex with this man right? >> correct. >> and the only time you'd actually seen him in person, in your whole entire life, outside of work, was four or five times. >> correct. >> i have no further questions. >> what we wanted the jury to think about her is that you're gonna shoot your wife for this? >> reporter: attorneys feuerhelm and owens then went on the attack, characterizing the work of investigators as woefully shoddy. >> the ayes have them -- inconsistent, incompetent, incomplete. thrust was on what the investigators did not do. this state criminalist had to

. >> reporter: he said her name was rachel mcfarland, but seth imdiately downplayed her importance. he said even lisa knew about r. >> but it wa't seeing her. it wasn't anything. it w just hey, how w you datype of thing. >> would it be condere sextg? >>o, no. noneat. >> whaare you wearing? no, there wn't any of that. lisa found out. everythi w kosher. i stopped talking, younow, we goover it. e ve to be honesout r, okay? ishere anything th you haven't told us yet? >> no. everything is going to add up the way i justd you. >> rachel's dna won't be maybe on your otheor >> iever had sexual -- sex with her.no, nothoral, nothing liketh that. i gave her hugs and i' kissed he >> repter:y now, seth's and were trying desperately to end the iew. t it wasfter hou and t outside w locke >> bang,ang, bang on the door, doug. is that you? >> that's me. that's me. >> they wouldn sp. >> they -- >> they didn't come out. >> didt stop. reporter:hey didn't have to. rememberseth was advised by agent th agent thas that was free to e me -- anytime. everhingasal. lead agent birming wating sethn monitoimy igd t