so in the early hours of the case, there was a lot of stuff swirling about kevin klym. across like a short-fused guy who sometimes got physical. >> at the end of that first interview with kevin, the boyfriend, is he on your suspect list of people of interest? >> yes, he is. >> reporter: he hasn't talked himself off the list? >> no. >> reporter: at the end of this 12 hours of grilling, kevin said he felt more like a prime suspect with a star next to his name. forget about person of interest. >> we know you did it. why did you do it? we don't think you're a bad guy. maybe you made a mistake, you know, and all this stuff. i'm, like, i can't tell you i did something i didn't do. >> reporter: in the court of public opinion, it was looking as though the boyfriend did it. but it turned out the 26-year-old dancer who so loved the lens had one final scene before the camera. a few seconds of grainy security cam footage. and what investigators saw there made them think that maybe the boyfriend was telling the truth. >>> coming up -- paula's last date with the killer. >> they liter