>> telling them the evidence would point to anna's ex-husband. >> the killer in this room is robert moses. there will be no doubt in your mind. >> walker was promising a strong case but what's a prosecutor to do about all those men in anna's life? she knew the defense would try to cast them as alternative suspects. no shortage of potential persons of interest here. >> anybody who is going to be an circumstantial case where there aren't any witnesses, you start looking at people and say who are the people closest to her? boyfriends? friends? anybody who had any relations with her? >> so in an unusual move, walker decided to preempt the defense and call those men as her own witnesses. she began with anna's boyfriend, michael who said he was intrigued by anna the day they met. >> she was an amazing woman. she was incredibly intelligent, very well spoken.