abandoned at birth, is determined to find his biological mom. >> so right now we're heading to cece moore'souse. >> hello. >> hi. >> come on in. >> i'm ben. >> it's very nice to meet you. >> likewise. >> reporter: cece has taken ben's dna and entered it into four national databases, hoping for a match to his biological mother. with possible hits on distant relatives, the dna detective's got her work cut out for her. but then, she catches a break -- a direct hit on someone they weren't even looking for. >> i logged into your match list a couple of days ago, and i saw this. r.b. is your father. >> reporter: ben does an actual double take. >> i had the same reaction. >> how did the planets align perfectly for that to happen? >> it's a man named richard blanshfield, who's a pretty incredible guy. he's a vietnam vet and he's not just any vietnam vet, he's a highly decorated vietnam vet. >> reporter: what are the odds? ben, a veteran of two tours in iraq, is now learning his biological father is a war hero. >> his arm was nearly blown off at the shoulder. he was 47 years old at the time of your b

. >> reporter: the answers came from genetic genealogist cece moore. >> we had enough to work with that was able to narrow it down to two full brothers. >> reporter: investigators say they arrested 59-year-old john miller, after matching his d.n.a. from the crime scene and from taunting notes he wrote to local residents threatening to kill again, to genetic information posted by his relatives on genealogy websites. investigators confirmed the d.n.a. match with evidence gathered from miller's trash. when he was arrested at his home sunday, miller reportedly confessed. what would you say to those out there who think they got away with their crimes? >> i think this case should tell them something different. >> reporter: this is the sixth cold case moore and her team have helped investigators crack, including the notorious golden state killer. since may, parabon nanolabs, where moore works, has uploaded more than 140 crime scene samples to a d.n.a. matching site, getting hits for more than half. gary grant and dan jackson were the original detectives on the april tinsley case. >> we're just

cece moore who appeared in "finding your roots" helped identify miller as tinsley's likely killer. >>hniques you use for an adoptee to find their birth parents. >> reporter: moore and dna sleuths unloaded the suspect's dna on a pub luck data base, gedmatch.com which found distant relatives in eight hours. moore built out family trees and zeroed in on people who fit the age, traits and location. a process that can take a few days to a few weeks. in tinsley's case moore determined her murderer was miller or his brother. on july 9th investigators secretly pulled used condomes from miller's trash and sent them to the crime lab. three days later con firmation. his dna matched the suspect's. >> i do appreciate the law enforcement agencies thinking out of the box who have jumped in and used this incredible technology to help bring closure to these families. >> reporter: since may, parabon nano labs has unloaded 140 crime scene dna samples to ged match getti getting hits for more than half and identified five cold cases across the country including the alleged golden state killer tied to doze

joining us now is our chief legal analyst dan abrams and genetic genealogist cece moore.ooking forward to this discussion. let me begin with you. you were able to narrow it down to two brothers, one is now behind bars, explain how you go about doing this. >> so we're looking for people who share significant stretches of dna with the suspect. we find them in the database ged match and then we reverse the family -- we reverse engineer the family tree of the suspect based on the family trees of the people that are sharing dna with him. >> how many cases have you been working on and are continuing to work on? >> i've worked on about a dozen so far. but i have many more cases waiting for my attention. so i expect that we will see lots more arrests thanks to genetic genealogy. >> i know families are hoping for that. dan, in this case too the suspect confessed. >> yeah, and you find that a lot of these cases where you're able to use dna evidence and they can present that to a suspect and say, look, we now have your dna. there's now new testing out there that can confirm you're o