>> david shannon knew, of course, that joan was seeing jeffrey wilson. e invited jeffrey to join them in the first place. but maybe he wasn't so happy about the cozy friendship joan seemed to be developing. that broke the rules. >> david told joan that she could no longer see jeffrey because he could see that joan and jeffrey had become romantically involved. and i believe it would have been sunday, she's actually having sex with jeffrey wilson, and actually david is killed in the early morning hours of tuesday. >> if you ask joan, and of course we did, wilson just didn't understand. didn't understand that the affair was actually winding down. why would he say you were in love with him then? >> he's a very self-centered and into himself and believes the whole world loves him. i didn't. we were actually pulling apart. it was coming to the end. >> really? detectives added it up and here's what they had. a story of some shadowy intruder that didn't seem to check out. the swinging, the affair. the story, true or not, that she wanted out of the marriage. and b