where was he that night? and knapp was ready with a story. >> he had been babysitting, one of his boys at his ex-wife's house when this incident actually occurred. >> you'd have to pin him down on that, make sure he had proof of it, right? >> that's correct. >> reporter: another detective turned on his recorder, as knapp rambled on about his relationship with carol. >> she and i are, sort of, commited to one another to be co-coaches to coach each other through both our divorces. >> reporter: but knapp didn't stop there. oh no. he seemed very eager to tell them about carol's ex-husband, steve democker. >> i'll warn you guys. it's just my intuitive take. the guy comes off to me as a very sneaky, manipulative man. >> reporter: so by the time steve arrived detectives were already suspicious. and they asked him to come to