back to dennis murphy with "and then there were three." into michelle martinko's 1979 murder had a new urgency. the detective doug larrison had a dna profile of the killer and original list of suspects. one by one he asked for dna samples looking for a match. >> doug started with the all the exboyfriends, the high school buddies that had been at the mall. >> at the top of that list was ex-boyfriend andy. >> i thought it was a matter of time before andy was found to be the killer. >> but andy's dna was not a match. more than 25 years after he was first considered a suspect, he was cleared. justice for andy. >> and he had to live with that cloud over him because so many people did think he was involved. >> curt thomas, the last person in her circle known to have seen michelle at the mall was also tested. police called his lawyer with the result. >> they got him on the phone and said the dna is not a match. they hung up. >> the deadline is the dna is not a match? >> right. >> another possible suspect cleared. another setback for the cedar rap

here's dennis murphy, without there in the dark. >> what is the next thing we have to do?or brandi daniels murder. they learned a lot about just how awful her marriage to josh was. cops found a 9-1-1 call brandi had made six months before her murder. >> i'm in a abusive relationship, and i'm afraid to go home. i tell my husband that i want to leave but he won't let me. it gets physical. >> brandi didn't request -- but she did follow restraining order against josh, when she left him. cops knew josh's body from the gym, serious, was likely involved in the murder. they just couldn't tie the two of them together, despite some suspicious phone traffic between the pair. an additional difficulty in the investigation was the fact that josh was still living in alaska, about as far away as you can get from ohio, and still be in the same country. josh daniel was -- living in waasila, about an hour after anchorage with his mother and stepfather. keeping tabs on him from thousands of miles away with the zanesville police. they were seeing some patterns. when he was a a job in the oil f

here is dennis murphy, with the unusual suspect. >> consider for a moment that cozy word home, and all it evokes. warren. family, shelter, security. got it? and now reflect on what happens when those four walls are breached, when nightmare stuff crawls through the window, kicks in the doors, when a haven becomes a house of horrors. so how does that feel? just ask floyd irving. >> i'm laying on the couch. i wake up in there's two gunmen over top of me holding guns, pointing them at me like hold it down, you're being robbed, don't move. >> here's a past that night in august 2000, a outside the nation's capital, in a nice neighborhood in prince georges county maryland. but lloyd and vicky ervin and their son, just four years at the time, are still haunted by the image of gunman. two masked intruders. >> talk about your worst nightmares. this is. it >> yes it's something you would never imagine would happen. >> what the robbers didn't count on was that lloyd is a nationally renowned martial arts expert. and when one of the gunman walked away to school but the rest of the house, lloyd was s

. >> that's dennis murphy reporting on it for nbc nightly news. >> they're known as serial killers andw enforcement officials, there are at least 35 of them roaming the country now. >> and these two admitted killers told police about one particular victim, in colorado. >> the confessed to committing the murder of helene pruszynski. what was unique about then is that detectives often thought that there might have been another person may be in the car waiting for whoever they took out into the field. that was one of the theories. >> so, these two guys who worked together, these powerful prolific serial killers, that certainly fit? >> it certainly fit. >> it's pretty seductive when a couple of serial killers who are on the hook for a lot of other murders confessed to your murder, because it would close a lot of cases if you can link them to these guys. >> that's right. obviously they were like, this is awesome. we've got a confession. >> colorado investigators headed for texas to interview lucas themselves. >> you're being questioned in connection with a crime of homicide. >> the detectiv

back to dennis murphy with shannon's story. >> after more than a week of theories, of speculation, investigatorsin these disappearance. an anonymous caller had left a cloth bag, like this one, carrying gianna's ring at the phone booth. could that be proof of life? is there a glimmer of hope here, that you're in a period of rounds of negotiations with whoever this caller was? >> and that moment, i kind of had hopes. you know, all of a sudden, i said, maybe we can recover. >> so you're waiting for another phone call? >> if this is about money, maybe we can -- there still a chance, that she still alive. >> the fbi was less optimistic. what was your instinct telling you? >> ten days out is a long time on a kidnapping. i think, in this instance, you can probably give it a little more possibility that she's alive because she was an adult. it's possible. >> with that new break in the case, the family stepped up its media campaign. >> we are living through every parents nightmare. we just want to shannon to come home. >> they started raising money for a possible ransom demand, canvassing the city with f

here's dennis murphy, with the girl with the red shoes. >> veronica kasper zach is a determined woman. >> if someone said you can't save them all. >> my mother is probably the one who would say that. but yeah i heard that a lot. >> she rarely was a. the desire to do good, to save a child was too strong. though, something in the quiet hours, she wonders if she did the right thing. >> if i didn't have that house, if i had not taken a shower. if i would have done something else, she would not have been in that situation. >> of course no one could have now and then that it would end up like this. >> police department, i need to report a one-way. my daughters missing. >> her daughter was annie grace, the when veronica first met her, she was not -- . she wasn't even her daughter. she was a client, just seven years old, with the rough childhood. >> she had been through some abuse, and she had a hard time trusting other people. >> back in 2005, veronica was a caseworker for utah's division of children services. her job was to find a home for kids who no longer had one. and he was one of those