rosa ortiz: she didn't get that chance.to raise her grandkids. dennis murphy (voiceover): as for derrick, he continues to help other people of color searching for missing loved ones through the nonprofit, black and missing foundation. but his personal journey is over. you just kept on a comin' and a comin' and a comin' for years. yeah, scared as hell sometimes that they were going to come and lock me up. how do you think about yourself, derrick? are you a hero? no, just somebody that cares about his family. i have no doubt in my mind that had this happened to me, that pam would have did the same for me. [soft music] [theme music] >>> i'm craig melvin, and this is "dateline."

rosa ortiz: guadalupe, and then eventually, he brings her over to the us.89. he's got two wives in the greater dc area. is that the picture? that is. somebody stashed over here in an apartment, living a life, and somebody else is somewhere else, and he's shuttling between the two lives? that's correct. dennis murphy (voiceover): and all in secret. dennis murphy: did she know at the time that he was married to this other woman named marta? she did not. she had no idea who marta was. she was totally in the dark on that. she was. dennis murphy (voiceover): what's more, jose had a son with guadalupe, too. what's that tell us about the guy, jose? he lived two different lives. so how do you pull that off? you learn how to lie to one wife, lie to the other wife. two women, two children. neither knows about the other, at least for a while. for a while, yes. dennis murphy (voiceover): marta's sister says eventually, marta got wise to jose and guadalupe. she knew. she told her sister that she knew they were married. interpreter: that's when the problem started, and s