>> reporter: police briefly detained sam, but he was back home by morning. now daron wyatt focused on javier. >> and we really approached it very low key. "we think that you can really provide some great information for us. would you mind coming down with us and talking." >> reporter: they brought him down to the station and listened patiently as he distanced himself from cathy torrez. >> he'd never been shopping with her, never changed a tire on her car, never carried groceries. we went through the whole litany of things that -- >> reporter: and he's all, "oh no, no, that's --" >> would -- >> reporter: that's all true. "i'm a million miles away from her"? >> right, right separated himself. >> reporter: but in so doing, javier ruled out any innocent explanation for finding his dna and fingerprint on her car. so when police told him that's exactly what they had found -- >> it was like vapor lock. and then all of a sudden he said, "well, you know, this one time i was at the video store, and i saw sam and cathy there together.