i was ready. i was, this is it. this is who i want to be with. this is who i want to grow old with. this is who i want to have kids with. reporter: and they did. a year later came a baby girl. and sam embraced his role as dad. he was like mr. mom, you know. he stayed home and took care of the baby while i worked. reporter: if sam had anything to do with cathy s murder, he certainly didn t act like it. he stayed put. living with his wife and baby right down the street from cathy s mom, mary. she would sit outside and stare at us, and i felt like she was doing it to make me uncomfortable, and probably him, too. but i m sure she didn t want him to be happy if she thought that he had anything to do with what happened to her daughter. reporter: sam say anything about mary? no. no. he would try to tell me to
reporter: to daron wyatt, it felt more like fate. and just months later, in january 1997, his lieutenant suggested daron apply to the homicide unit. so i ended up putting in for that job and being selected. reporter: it wasn t long before he cracked open the doors that housed the homicide files. and i open the cabinet and i see the torrez case. and i remembered the incident with debbie from about a year earlier. so i pulled it out and i started reading just on free time, just reading it a little bit. reporter: by then, the cathy torrez case had been cold for a good three years. and essentially no work had been done on it for at least the last two years. reporter: from the beginning, police had suspected cathy s one-time boyfriend sam lopez had something to do with her murder. but they had nothing connecting him to the crime. no witnesses. no dna. and sam had that solid alibi. tina was still married to sam s
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? reporter: that led the detective to take a fresh look at those bizarre events the week before cathy disappeared when she came home impaired and then had her tires slashed. she never regained ful
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. and i went and i sat in cathy s car and sat in the backseat and waited for them. and they came out and then i left. and that was really his only contact that he could give us with cathy s car. reporter: but he doesn t fold up
back in 1994, police suspected sam lopez of killing his sometime girlfriend, cathy torrez, but they couldn t make the case. one big reason sam s cousin, javier, who told detectives he was with sam the night of the murder. javier was sam s alibi. so he wasn t suspected of being part of the murder, or even being at the crime scene. that s right, yeah. they were looking at javier solely as an alibi witness who was lying to cover for sam. reporter: that s why, as detective daron wyatt now discovered, even though investigators in 1994 took blood, hair and fingerprint samples from javier, they d never had those tested. they had sent all of the evidence related to sam lopez to the crime lab, his fingerprints, his hair, his blood.