and for ben tveight, it is the final step in finding the missing link to his past. chorage police station. >> hi. >> dave cook. >> nice to meet you. >> reporter: believe it or not, he locates the detective who was one of the first on the scene three decades earlier. >> you didn't have any physical trauma, anything like that. the umbilical cord was tied up with a sandwich tie. >> reporter: their most promising lead, that police sketch of a possible suspect, never got an i.d. >> there were several possible prints, but they were poor and not very useful. >> if fingerprints were lifted, would they have been preserved? >> we're talking 30 years now. >> right. >> and basically all the photos have been destroyed, the prints have been destroyed. >> reporter: and yet again, old-school crime solving is futle, leaving it for cutting edge dna technology to save the day. but genealogist cece moore's been able to identify two of ben's second cousins. she traces their family trees, all the way to their great grandparents. she then builds the family trees forward with their decedent