Transcript for DNA tests shows 3 of 4 Bear Brook victims related, 'Lisa' ID'd: Part 6
I think if I tried to write it as a fictional story people would say it's unbelievable. How could you have a family disappear? At this point I'm so obsessed with the case. Let's face it -- there's a lot of dead people in the case tied to Evans. He had this little girl that he said was his daughter, and he gave her away. So then the mystery becomes, where is her mother? Because we know this guy kills people. These were people he lived with. And at the end of the story, the guy that did all that is your father. My father is a serial killer. Could have been me. Whenever people ask me who the worst serial killer is, I have one answer. It's been more than 30 years since the discovery of the first barrel in allenstown, new Hampshire. State police begin to work with the national center for missing and exploited children to revive the case. And they come up with new composite images of the victims, composite images of the victims, more high-tech reconstructions of what the victims might have looked like in life. This is the skull, the ct scan brought into our software of the oldest child. You can see the blunt force trauma, the fracture lines here. You sculpt the muscles back on the skill, and then slowly start to work on each individual feature to come up with a final rendering of the face. Investigators reveal the new images of the woman and three children, whose identities remain a mystery. They gave some measure of humanity to the victims and just helped to remind everybody that these were real people. So, in addition to constructing facial recognition of the victims, they also did DNA testing to determine, are they possibly related? Forensics show the woman is related to two of the children, most likely a mother and two daughters, but one girl is from a different family. So who was the middle child? Became even more of a question. The goal was to not only report what we found but to engender interest in the case, because it was constant discussion about the fact, how can an entire family be wiped out and no one come forward? We hope that maybe somebody would remember something out there and make a phone call but that didn't happen. So as the New Hampshire investigators are falling flat in their case, Lisa in California is still trying to figure out her identity. Around 2015, more than a decade after Lisa found out that the guy that had abandoned her wasn't her real father, she comes up with an idea. She hears that there are people using DNA websites to find long lost relatives. Why couldn't that work for her? The databases had grown tremendously. So we signed Lisa up on ancestry initially, and we started getting some distant cousin hits. They are fourth cousins and fifth cousins. And it's not simple to find out someone's identity based on the identity of a relative who's that distantly related. I emailed DNA adoption and I asked if the techniques they use for finding the bio families of adoptees could also work for Lisa. It was Dr. Barbara rae-venter that responded. So, genealogy itself is doing family history research. Genetic genealogy is when you then couple that with DNA. The Lisa case was actually kind of difficult, because normally when you're working with adoptees, you have some information -- you know where they're born, you have a birth date. And in Lisa's case, we had no idea where she was from. All we had was her DNA. We had from her dental development from when she was first recovered back in 1986. It had been estimated that she was probably born about 1981. At the time that I started working on this case, Lisa was about 35 years old. Barbara spends thousands and thousands of hours trying to figure out who Lisa is related to. She builds a family tree, and ultimately it leads to a man in New Hampshire, who is Lisa's grandfather. I was contacted one day by my nephew, and he was working with the sheriff's department out in California. And they requested for me to do and they discovered that I was the actual grandfather. And Barbara rae-venter learns from him that he had a daughter named Denise Beaudin, and Denise is Lisa's mother. I called Lisa up to let her know that we knew who she was. She got very quiet. I asked her, do you want to know your name? Then she just very quietly said yes. It turns out that in fact Lisa's birth name had been dawn Beaudin. Dawn was born in 1981. She was only 5 months old when they left Manchester. The last time Lisa's grandfather had seen Lisa and her mother was in 1981 around Thanksgiving in Manchester, New Hampshire, with the mother's boyfriend, a guy by the name of Bob Evans. Bob Evans had apparently told family members at Thanksgiving that they were going to be leaving town. That they owed people money and so they would be leaving. A week later on the 1st of December I went over there to invite them here for Christmas and found out that they were already gone. The neighbors told me that they had packed and just left. And I never saw her since after that. We had no idea what to do or where to go or which way to turn. The presumption was that they were just going off to make a new start elsewhere, so when they left the area, her family did not file any type of missing person's report. And no real inquires or follow-ups or communications beyond that were had with her family. One of the first questions for investigators is, who is this Bob Evans guy? He's a guy who was a plumber, electrician. He would do trade work. Kind of like a tall, heavyset man. Kind of rough looking, you know? I didn't really take to him too much. He looked kind of shady. So, here you have the last person who's seen with Lisa in New Hampshire, Bob Evans. The next time we see her is in California with Gordon Jenson. Maybe it's the same person. I sent Manchester P.D. Pictures of the guy we knew as Curtis Kimball and Gordon Jenson. Authorities go to Lisa's grandfather, they bring a mugshot of Gordon Jenson, the guy that had abandoned Lisa in California, and they show it to him. And right away he recognizes him and confirms what investigators had feared -- that Gordon Jenson was also Bob Evans. Detective Peter ahead Hedley called him a con man. The prosecutor had another name for him, the chameleon. He clearly had the ability to ingratiate himself to other people, to mold himself to the situation to get what he wanted. By this point investigators had connected three of the four mysteries with each other -- eunsoon Jun's murder, the identity of Lisa, and the disappearance and presumed murder of Denise Beaudin. After 30 years, in 2016 police open a missing persons case on Denise Beaudin. She had not been reported missing before then. Then a case manager at the national center for missing and exploited children looked at a map. Manchester, where Denise Beaudin was last seen, was only about 25 minutes from bear brook state park. Denise went missing in 1981. The first barrel was discovered in 1985. We started to look at the timeframe and the proximity and we're like, wow. There's a potential that these two cases could be related. So, investigators wondered, is Denise the adult victim from the first barrel?
This transcript has been automatically generated and may not be 100% accurate.