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. but they hadn't sent anything related to javier lopez to the crime lab. >> reporter: daron sent javier's