win instantly. >>> detective daron wyatt never believed xavier lopez had acted alone. 997 for the murder of cathy torrez, he thought xavier's real role was helping the prime suspect -- xavier's cousin sam lopez. tina montelongo, sam's then-wife and xavier's friend, wasn't buying it. can you conceive of xavier going through with a murder or being involved in it because of his loyalty to sam? >> no. i don't see that. if sam did it, would xavi help him just because they're close family? i don't see that. >> reporter: neither did the d.a. who decided there was not enough evidence to file charges. how do you tell mary bennett, "we had xavier, but we had to let him go"? >> it was extremely difficult. there was a lot of crying on both sides. >> reporter: daron knew exactly what releasing xavier really meant. what walks out of the jail along with xavier is any leverage you had to get him to name sam? >> yes, absolutely. >> reporter: and now you really are back to square one? >> yes. >> reporter: is that the end? >> to some people. >> reporter: but not to him. and not to mary. y

daron wyatt was confident he had enough evidence to prove xavier lopez had killed cathy torrez. orange county district attorney did not agree. the d.a. decided not to charge? >> correct. >> reporter: and so xavier's set free? >> xavier walks. >>> a detective who refuses to quit -- >> i said i have a cold case i need you to take a look at. >> reporter: now has a reason not to. >> my first daughter was born. and i remember going to mary shortly after that looking in the eye and saying "i know. i know now how you feel." are yom with an old computer? that's like lebron... ...trying to perform with old equipment. ♪ ooh. well that is not what the fans signed up to see. is outdated equipment holding you back? upgrade your game to intel's fastest processor. you should probably upgrade those, too. ♪ (vo) living with ammonia odor? not a pretty picture. (vo) luckily, tidy cats lightweight with new ammonia blocker tackles tough odor, even ammonia. so long stankface! (vo) ammonia like that? there's a tidy cats for that. from our crazy delicious family to yours. the energy conscious whopeople