which called into question sam s story. it does. reporter: and daron noticed another inconsistency in sam s account of the days right before cathy disappeared. mary, however, says sam was the one calling her home looking for cathy. he called how many times? quite a few times looking for her. reporter: mary says sam sounded okay at first, until she told him where cathy was. i said she was at the hospital and she wasn t back yet. reporter: at the hospital, visiting albert, her boyfriend, who had attempted suicide. sam okay with that? fortified. emerge everyday with emergen-c. packed with b vitamins, electrolytes, antioxidants, plus more vitamin c than 10 oranges. why not feel this good every day? emerge and see.
and the physical evidence seemed to confirm it. sam s dna was not found anywhere on cathy or her car and his clothes, the ones he gave voluntarily to police, had no dna of cathy s on them. but that behavior of sam s which bothered cathy s family, also bothered police, and they focused on him. however, when investigators took their suspicions to the orange county d.a., the outcome was not what they expected. coming up, sam has a new woman in his life who soon discovers his old life. you were a little freaked out by that? well, yeah. love. only activia has billions of our live and active probiotics. love. a delicious way to enjoy probiotics every day. with 20 years of devotion to gut health. activia. like no other.
were in high school, lived across the street. cathy s older sister was married to sam s older brother. reporter: they had this long on again/off again relationship in which what, he couldn t let go of her or she couldn t let go of him? i think a lot of it was mutual. reporter: even after cathy started dating albert and sam had another girlfriend, too, they continued to see each other. and daron found evidence that in sam s mind, his relationship with cathy was far from casual. mary gave me a shoe box full of letters that were written between sam and cathy, and the content of these letters showed a very jealous guy. a guy who would get angry any time somebody flirted with cathy. reporter: sam didn t try to hide the fact that he was prone to jealousy. she knows, every time she mentions some guy s name, i get pissed off, okay?
and yeah, it looked really tough. reporter: but what really made this case a prosecutor s nightmare was the fact that all the physical evidence pointed away from the man they thought was the killer. any defense attorney would ask, if police found javier s dna and fingerprint, why would they charge sam? were you surprised you didn t find sam s dna there? yes. reporter: he thought newer, better tests might find sam s dna, but it was too late for that. cathy s family had sold the car. the case against sam would have to be entirely circumstantial. murphy felt the key to that was somewhere in those interviews sam gave to police. but here, too, there was a problem. when you look at the interview, everything that sam lopez said seemed logical at the time. and everything seemed to make sense. reporter: picking apart those interviews would be critical. this is one of those cases where you have to look at the details.
little bungalow with his wife and his baby at the time, yet javier was there all the time, sleeping in the same essentially the same room. reporter: eventually, daron wyatt felt he had enough new information to get a search warrant. there was a loud pounding on our door. reporter: tina montelongo remembers it clearly. when i opened the door, there was about five police officers there. the one in the middle was wyatt. he put us against the wall and patted us down. reporter: what was sam s demeanor while all that was happening? he was calm, you know. he really was. i was freaking out. reporter: he wasn t worried? no. no. reporter: maybe he had no reason to be. police didn t find anything in the house linking sam to cathy s murder. they even sprayed his truck with luminol looking for signs of blood. we took the seats out, we did everything we could. and there was nothing.