reporter: detectives were now certain that je michael was danielle s killer. and they knew where the investigation was going next. they had to deconstruct je michael s alibi, the one that put him home studying that night. it turns out the family members who said they were with him, weren t actually in the same room with him. they couldn t say they d seen him with their own eyes. we actually could not get confirmation from mother or grandmother that he was there. reporter: which meant the only person truly vouching for him was his study partner and best friend, dominic. we brought him to the sheriff s office, gave him the same opportunity and he lawyered up. reporter: did you go through this scenario, that you re two guys in trouble. and one of you might be able to do yourself some good. we let him know, very bluntly, that the house of cards is falling. the first one on the train gets the ride. reporter: four days later, police got a phone call. it was je michael. i got
reporter: in fact, he d been interviewed aggressively by veteran investigators. and he never buckled. if you killed this girl, or you had anything to do with it, you re gonna have every law enforcement agency around gunning for you. yes sir. yes sir. reporter: but that didn t stop investigators from giving je michael a polygraph. and in his cool exterior, they thought they saw a crack. absolutely bombed it. he flunked it? absolutely. reporter: they suspected he was lying. but je michael never changed his story. to rattle him, they d even played some extreme games. reporter: now that danielle s body had been found, it was time to dial up the pressure. investigators would pay je michael a visit at his house. they set the stage in a church parking lot. we briefed everybody on what was gonna transpire, who was on perimeter, who was goin in did you have your vests on, firearms out? we did. we had everything with us. reporter: while several officers kept an eye