>> we got three calls, we think one of them was the kill glory so we didn't know which one. >> so you got a live one here? >> we got a live one here. >> what do you think at home? >> we were ecstatic. we were ready to go. >> he was sitting right there. it's hard to enjoy your food when you think you are staring at the killer. >> hello, well come to "dateline." teenager michelle martinko was blessed with beauty, brains and compassion. her life was cut short when she was savagely murdered. that dreadful night was ice cold and after four decades, so was her case. then a stunning scientific break through helped detectives whittle down a list of suspects to unmask a killer hiding in plain sight. here's dennis murphy with -- and then there were three. >> it was an act of unspeakable violence. >> it was a really hor risk crime. everybody was scared. >> a murder that shattered a family. >> my parents were devastated. my mother eventually did not go out of the house. >> a whodunnit that grabbed ahold of a city and wouldn't let go. >> it hung over the community for 40 years. >> a case that questioned investigators until the killer quit. >> in solving this murder, they were working and they didn't. >> curt thomas says he was a lucky kid. he got to grow up in cedar rapids, iowa. >> it was a magical bubble. we didn't know anything but fun. >> a lot of that fun happened at the mall. for teenagers, it was the place to shop, eat and happening out. >> that's where the kids hung, huh? >> it was a place you could go any time, it was a big deal. >> high school senior michelle martinko was no mall rat, but she did shop and work at one near her home. official was a top student, a gift baton twirler and sapping in the school choir along with her friend jane hansen. why do you think you guys hit it off so well as you did? >> we had a lot of things in our life that were parallel. >> was she what they used to call a girly girl or was she a bit of a to himboy? oh, no, she's a girly girl. >> she looked like an angel, farrah. >> it was farrah faucet majors time. >> with the hairdo. >> with the hair. so she was farrah. >> reporter: though it was a school night. after the bank wet, michelle asked jane to go with her to the mall. but jane had homework to do. so when she said, let's go to the mall, that wasn't going to go with you? >> correct, i turned her down. >> so going solo, michelle got her parents' 1972 abuse of congress electra and headed off to the new westdale mall. on the southwest side of down u town. she had $180 in cash to pay for a coat her mother had picked up. >> it was i saw this beautiful girl in a rabbit fur coat, black dress, high heeled shoes, blond hair. then i was like, that's michelle. >> it pops in my head, i'm never going to get a dance with that girl. >> i got miss america here on my arm if. >> yeah. >> reporter: he said they spent tear entire break catching up. until he had to get back to work. >> that's when we're saying our good-bye. and she says, well, don't be a stranger. >> did you think you'd see her again? >> yes, of course, i did. >> since there was school the next day, it wasn't a fight to stay out late. when she didn't come home, her sister said her parents started worrying. >> my parents started calling around her other friends, what the situation was. >> why she is not back here at home? >> yes. >> janet did call the police as well. we can't look for every teenager missing for hours. janet resisted that, she should be home. she has a test tomorrow, she has to study. >> michelle's mom kept making calls late into the night. at 2:30 a.m., she dialed michelle's friend jane. >> i was sound asleep and my dad came and woke me up and you know said it's mrs. martinko on the phone. >> those are not good calls. >> she wanted to know if i knew where michelle was. >> but jane didn't know. nobody did. so in the mild of the night, a pa a panic. they called police again. this time they dispatched an officer, jim kinkead got the call at 4:00 a.m. >> they sent me out to the mall to locate this car ro. hours earlier the mall was bustling with christmas shoppers. now it was dark, deserted. in the distance, officer kinkead spotted a car in the far reaches of the parking lot, a long walk from the entrance to the jc penney. >> it seemed to match the description of the one i was sent to find. >> looking from your vehicle, could you see what had happened there in. >> no. >> you couldn't see in the windows? >> they were frosted over. i opened the back door, i could see that there was a woman slouched down. at first i thought just an intoxicated person. so i walked around the car and looked in the passenger's side front window and obviously it wasn't an old woman drunk. >> could you tell she was gone? >> there were no signs of life. she was now deceased. >> beautiful, vivacious high school senior michelle mar tip martinko was dead. the brand if you westdale mall had become a crime scene. >> coming up what had happened to michelle? >> a very frenzied attack. there was blood everywhere, there was blood splatter all over the car. >> michelle had deep defensive wounds against her hands. she put up a fight. >> against a man who knew what he wanted. >> the officers found blood on the car, on the door handle. >> so the business came to do business? >> i don't, yeah. o business >> i don't, yeah . >> when "dateline" continues. >> when "dateline" continues. >>s stop by lowe's now, for your happiest spring. with downy infusions, let the scent set the mood. feel the difference with downy. ♪ it's the most wonderful time of the year, ♪ claritin provides non-drowsy symptom relief from over 200 indoor and outdoor allergens, day after day. feel the clarity - and make today the most wonderful time of the year. live claritin clear. ♪ ♪ i'm the latest hashtag challenge. and everyone on social media is trying me. ( car crashing ) but if you don't have the right auto insurance coverage, you could be left to pay for all of this... yourself. so get allstate. as a business owner, your bottom line yourself. is always top of mind. so start saving by switching to the mobile service designed for small business: comcast business mobile. flexible data plans mean you can get unlimited data or pay by the gig. all on the most reliable 5g network. with no line activation fees or term contracts... saving you up to $500 a year. and it's only available to comcast business internet customers. so boost your bottom line by switching today. comcast business. powering possibilities.™ >> on a dark, ice cold morning, cedar rapids detectives were called to the mall parking lot to begin a murder investigation. the body of michelle martinko in her black dress and fur coat was slumped halfway off the passenger's seat of the family's abuse of congress electra. >> she had multiple stab wounds. >> doug larrison was a college freshman when she was 12. he met her in kindergarten. they had come to know every detail of this case. >> a very frenzied attack. there was blood everywhere, there was blood splatter all in the car. >> did the killer leave a blood trail, did you get luck why i? >> the officers found glove pripts on the outside of the car, in the dirt on the door hand him. they look like dish washing gloves from the late '70s or early '80s that everyone would have in their house. >> so the killer came to do business? >> yeah, the killer came to do business. michelle has deep defensive wounds on her hands. she put up a fight. >> the drug told them the struggle happened mostly on the passenger's side. but. >> the steering we'll's got blood on it. we know michelle is not driving the car. >> what does that suggest to you? what's the connect the dots thought? >> the connect the dots thought is the killer is touching these things after they murdered michelle. >> they thought the killer left his own blood behind. but linking that to a suspect in 1979 almost impossible. >> they didn't have dna analysis. they used type a blood or type b blood, which doesn't narrow it down very much. >> still, police collected the blood for analysis. there wasn't much else at the scene to point to a who or why behind the killer. >> there were no obvious seeps of sexual assault. we didn't have a good foundation for deciding what the motive was at that time. >> that left investigators back in the day happy. >> it's almost like this is the heartland of the country and no place is safe anymore. >> we got the call about 6:00 in the morning, maybe 5:00 in the morning. >> janelle stonebreaker, michelle's parents broke the awful news to her through sobs and pleas. >> they were devastated. >> even then, she sensed her parents might never recovered, even though they wild here in this world. >> this is my mother and father's miracle baby. she's the child they had tried to have for all those years. >> a child to who grew up in 1960s and '70s in mid-town america, hanging out at the roller rink. a back brace for scoliosis turned her into a shy teen. by high school, she did a 180. >> when she got her braces off, she blossomed. >> they walked these same halls with michel, three close high school friends. >> all the time she spent not wanting to be noticed, then she spent to be noticed. that's when the hair changed and she got into her fashion, her style. >> the farrah hairdo worked for michelle, she, in turn, worked it. she was a head turner, is that it in. >> she was a head turner, that was it. >> i think she knew what it was like to be on the other side of that she would go out of her way to be kind to everyone. >> oh yeah. >> that mix of beauty and sweetness made mike a year ahead in school fall for her. >> i was really serious. this was my first girl friend. it was the most serious relationship i ever had. >> it ended when he went to college. she dated and broken up with a guy named andy. her friends thought andy had a hard time legislate go, which may have prompted this exchange. >> she was a little weepy in class one day, i asked her, what was going on, her response is she was tired of belonging to somebody. >> her senior year, michel was focused on college. >> she definitely conveyed to me she was ready to put high school in cedar rapids behind her. >> reporter: curt thomas, the boy she hung out with is certain michelle was preparing to leave the building when they said their good-byes. >> you don't think that person is going to walk out the door and you will never see him again. >> curt says he feels guilty how he handled that good-bye. >> i could have walked her to the car. i could have done something. >> we're standing where her vehicle was found. now, more than 40 years later the account of michelle's final stems to her car is mostly guesswork. >> just around the jc pennies would have been the entrance she exited from. >> i'm thinking it's a good walk. >> it's a long walk, mid-december. the lot is probably not real well lit in 1979. yeah, she's got a long walk. >> reporter: a long walk through a dark lot. now police were eager to speak to one of the last friends known to have seen michelle martinko alive. coming up. >> the principle turned and said, mr. thomas, i need to talk to you. okay. >> a possible suspect. >> it was just like they do it on tv. this guy leaned over and said, why did you kill her? talk about deer in the headlight-looking kid and an ugly rumor. >> the theories were just awful. it went everything from drug rings to prostitute rings. >> when "dateline" continues. ri. >> when "dateline" continues houn tell you how a young homeowner is turning into their parents. -not those two. -yep, they're gone. -forever? -yep. that there is progressive's homequote explorer website, where i compared home insurance rates. we don't need to print the internet. some are beyond help. i will give you $100 if you can tell me what this is. -scotch egg. -it's a meatball. progressive can't help you from becoming your parents, but we can help you compare rates on home insurance with homequote explorer. we've got a lot of work to do. 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>> now is the time to give it up and give yourself some good. >> talk about a deer in the headlight looking kid. >> then his store manager was on the line. she said curt turned on break, returned about 9:30 and helped her close up shop around 10:00. police believe michelle left the mall some time in that half hour. >> this detective said, mr. thomas, you can go. i didn't know what that meant. as stupid as that is to say, can i really go? >> for the moment at least curt was in the clear. in fact, michelle's brother-in-law, john, already had someone else in mind for her murder, her old boyfriend andy. >> he was very obsessive. after they broke up, he parked down the street to see if she was going out with somebody else. i was sure it was andy, if i can't have her, no one else can have her type of thing. >> they understood why the first detectives took a lard look by andy. >> why was he there? >> he was there to buy her a christmas present. >> her, the ex-girlfriend, the night she is killed, he is at the mall to buy her a present even though they are flo longer a boyfriend/girlfriend? >> yeah. correct. >> that sounds curious now. >> a lot of detectives thought that might be too much of a coincidence. >> andy recounted his movementles. he and a buddy bumped into michelle around 8:30. he said he had no idea michelle was missing until her mother called his house about 3:30 a.m. he told detectives he and his mom went in the car to go searching but couldn't find her. >> is the early thick we will get with this young guy andy and we'll have a soft case here? sweat him a bit and the story will come out? >> his story never changed. they had no physical evidence to connect him to the murder. and without a quick arrest, the cedar rapids gossip mill started churning. as time went by, people became suspicious of michelle, herself. >> the theories were awful. it went from everything from drug rings to prostitute rings. >> to somehow this young girl i girl brought it on herself. >> absolutely. surely, she had to be at fault in this. >> painful for your parents? >> horrible. my mother eventually did not go out of the house. she just stayed at home. >> reporter: michelle's death and the failure to find her killer also had a profound effect on the city where she had lived. >> people were really upset and traumatized by it. >> reporter: the courts reporter for the cedar rapids' paper the gazette. >> back then it was smaller than it is now. it was a close-knit community. >> it was very mayberry like and honestly what happened to michelle stripped away not just our innocence, but the innocence of the whole town. >> it settled over the city, that michelle's killer may over in be caught. the '70s became the '80s and then the '90s. in 1997, they sent scrapings from the gearshift of michel's car to a state lab. >> the lab was able to sort out those dna points and left a dna profile. >> at the time it wasn't enough to match to a suspect. but in twoivgs doug larrison took over the case. he wondered if anything else from the car might yield a more complete dna profile and sent michelle's blood-stained dress back to the lab. >> got the call from the analyst they had found a full dna profile on the dress. that's exciting. >> that's and are you sitting down phone call in. >> correct. all we had to do is submit it to code is. >> codeis? >> it contains millions of dna profiles collected from crime scenes, from jails, people who have been arrested. >> did anything come back? >> nothing, no hit. >> to larrison, that meant michelle's killer was likely someone without prior arrests or run-ins with the law. that meant the people police talked to back in the day had to be reconsidered. >> my thinking is, let's start going through this case, finding potential suspects and go get their dna and start eliminating them from that partial profile. >> so now we're back to andy and all those other boyfriend in. >> correct. >> nearly 30 years after michelle's death everything old was new again. boys withal buys back in '79 were now middle-aged men with something more valuable than a story to offer. they had their dna. coming up. we're going to take a molecule of hemogenetic material. >> using dna to face a portrait of a killer and face his family tree. you got a live one. >> a live one only 20 minutes away. >> what do you think at that moment? 1234r we're ecstatic. you can taste it at that point. we're ready to go. >> when "dateline" continues. > we're ecstatic. you can taste it at that point. we're ready to go. >> when "dateline" continues. > we're ecstatic. you can taste it at that point. we're ready to go. >> when "dateline" continues. > we're ecstatic. you can taste it at that point. we're ready to go. >> when "dateline" continues. > ace and body. it's the only treatment for td that's one pill, once-daily, with or without food. ingrezza 80 mg is proven to reduce td movements in 7 out of 10 people. people taking ingrezza can stay on their current dose of most mental health meds. don't take ingrezza if you're allergic to any of its ingredients. ingrezza may cause serious side effects, including sleepiness. don't drive, operate heavy machinery, or do other dangerous activities until you know how ingrezza affects you. other serious side effects include potential heart rhythm problems and abnormal movements. it's nice people focus more on me. ask your doctor about ingrezza, #1 prescribed for td. learn how you could pay as little as zero dollars at ingrezza.com. michael: my tip is, the worst lies are the lies you tell yourself, like smoking isn't that dangerous. announcer: you can quit. for free help, call 1-800-quit now. ♪♪ for free help, add downy to your wash for all the freshness and softness of home. even when you're not at home. feel the difference with downy. ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ xfinity mobile runs on america's most reliable 5g network, but for up to half the price of verizon, so you have more money for more stuff. this phone? fewer groceries. this phone? more groceries! this phone? fewer concert tickets. this phone? more concert tickets. and not just for my shows. switch to xfinity mobile for half the price of verizon. that's a savings of over $500 a year. switch today. . >> hello, i'm darragh braun, governor ron desantis signed a bill, reversing the 85-year agreement that allowed disney to self-govern, it comes after they spoke out against the state's don't say gay bill. many fires are burning across the u.s., in arizona it's burning 2100 acres sense last sunday. 11 million people are under red flag zones in colorado and mexico. now back to "dateline." zblmpls zblmpbls "dateline. zblmpls zblmpbls . welcome back to "dateline." i'm craig melvin. michelle martinko's unsolved murder marked a loss of innocence for her friends and family, but not a loss of hope. cold case detectives were determined to catch the killer using a modern arsenal of tools. the same technology used to crack a legendary case in california was about to reveal a tantalizing clue. back to dennis murphy with "and then there were three." the decades old investigation 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 rapids pd. but when matt den linger took over as lead investigator in 2015, he thought dna would solve the crime. so he did another deep dive into a case file built by so many before him. >> now we're trying to find men listed in these reports that could have possibly had a connection to her or men that would have had a connection to the mall. i thought eventually if we swab enough people, we're going to come across our suspect. >> reporter: but after more than 125 tests, no one matched the killer's dna. they were out of leads. >> and then parabonn comes in, what is that. >> they create an image, an actual -- >> like up in the post office photo be on the lookout for this guy? >> exactly. computer generated police sketch. >> excuse me if i sound skeptical. that sounds like voodoo. you take a molecule and turn it into an image of somebody? >> correct. >> the suspected killer imagined at age 25, another at age 50. one with a typical 1979 haircut. police released the pictures to the public. >> we were hoping that 100 people would call in and say that looks like person a. the problem is we got 250 call in and say it looks like 100 people. >> oh, man. more needles, jorgestacks? >> a lot of rabbit holes, i tracked down another 50 people and swabbed them. each time hoping that this, we would find our guy. >> but with each dna test result, that hope was dashed. then in 2018, parabonn helped solve the golden state killer case, using a new technology called genetic geneology. >> i got an e-mail from parabonn, hey, check out what we did. >> they offered a senior geneology, they tried to identify relatives of the killer searching through genetic profiles. den linger gave them the green light. >> we set that in the spring of 2018. by the summer, they had sent us a report. they said they had found a relative of our killer. >> a relative of your killer in. >> yeah. they hypothesized she was a second cousin once removed from our killer. >> wow, there is a headline for you guys? >> yeah. >> the person was a woman live figure vancouver, walk. now the trick is to build the a family tree to see if police could link a family member to cedar rapids in 1989 she reached out to the woman and agreed to answer all the questions. >> we have to build her family tree. >> he pleased it through 1,800. >> you are looking through old records, census data? >> absolutely. >> tombstones, anything we could find. >> he created four branches, back to great, great grandparent. one led to ohio. he got a dna sample. >> we sent their dna to parabon. they recalibrated and told us we can eliminate that branch in the family tree. >> don't waste your time on that tree. >> this one here we wound up in nebraska, sent that in, same thing. >> boom. >> get rid of that one. we don't need to worry about that branch of the family tree. >> on the next branch, den linger found a relative living in iowa. so you had a live one at the bottom of the tree. >> this was a gal in lisbon, iowa. she's 20 minutes away. >> she's not the killer. >> we knew the killer was a man. we sent her dna to parabon. boom. she shares enough dna with the killer to be a first cousin. >> it turns out she shared it with three first cousins, three brothers. after four decades and so many disappointments, the suspect list had narrowed to three. >> all three of them are still alive, still living in iowa. >> what do you think at that moment? >> we're ecstatic. you could taste it at that point. we're ready to go. >> detectives are about to get up close and personal with the three brothers without them knowing it. coming up. >> and he decided to leave. we grab the cup off the table. my partner put some gloves on, grabbed the straw with the glass, package it up and disappear. >> then not a confession but not a denial eater. >> what happened that night, did you murder -- >> test the dna. >> when "dateline" continues. n s . isn't that right, frank? i saved 25%. booyah. you protected your casa? sure did. and the frank tank? you know it. and now you're relaxing. i'm working from home. sure you are. alright i see a lot of head nods. let's circle back tomorrow. you weren't kidding. save up to 25% when you bundle home and auto with allstate. click or call for a quote today. welcome to allstate. save up to 25% when you bundle home where you can bundlete. home and auto insurance. right, frank? i saved 25%. booyah. and now you're relaxing! we're working from home. save up to 25% when you bundle home and auto with allstate. my mental health was much better. my mind was in a good place. but my body was telling a different story. i felt all people saw were my uncontrolled movements. some mental health meds can cause tardive dyskinesia, or td, and it's unlikely to improve without treatment. ingrezza is a prescription medicine to treat adults with td movements in the face and body. it's the only treatment for td that's one pill, once-daily, with or without food. ingrezza 80 mg is proven to reduce td movements in 7 out of 10 people. people taking ingrezza can stay on their current dose of most mental health meds. don't take ingrezza if you're allergic to any of its ingredients. ingrezza may cause serious side effects, including sleepiness. don't drive, operate heavy machinery, or do other dangerous activities until you know how ingrezza affects you. other serious side effects include potential heart rhythm problems and abnormal movements. it's nice people focus more on me. ask your doctor about ingrezza, #1 prescribed for td. learn how you could pay as little as zero dollars at ingrezza.com. one by poise® is our first pad that handles period weeks and bladder leaks. which is just what you need while you handle... ♪ [upbeat music] ♪ stay clean, fresh and dry while you handle it all. find it in the fem care aisle. . >> and then there were three. after chasing down hundreds of leads over four decades, the suspect list in michelle martinko's murder narrowed down to three brothers living in iowa. when you run criminal records, anything come up? >> no. >> so they're leading respectable middle age lives as you can see. >> pretty much. >> they were adults in 1979, did not seem to have any connection to michelle martinmartinko, deco collect dna from all three. this is when you become a double-o act. it is shifting gears here? >> it is shifting gears. >> they start with middle brother kevin, a married father of three, he sold farm equipment in manchester, iowa, about a 50-minute's drive from cedar rapids. >> we check his dna from a straw. it immediately goes to the state lab. they told us, hey, he is not your suspect. >> the next brother was donald. >> oldest brother donald was a father of three and had five grandchurn. he lived in davenport, iowa and the manager of a lumber yard before retiring. he went to his house and staked it out surreptitiously. >> the first thing we collected out of a trash bag and checked dna off the toothbrush. >> what did the lab say? >> the same thing. he's not your guy. >> it came down to the youngest brother jerry burns, who like brother ken lived and worked in manchester. denlinger did intel on him. >> in noon 79, he had two young kids, lived in manchester, sold farm implems. he was in a bowling league. >> he's a married to children and 5:00 to 9:00 guy. >> yeah. >> he and his team set out for manchester in three unmarked cars police followed him throughout the morning, finally at lunchtime an opportunity. burns and his son had pulled into the pizza ranch restaurant. >> he parked in the parking lot there. he went in and was 60 at a booth by the window there. >> he and his partners went in and sat in the booth. >> you were in the next booth over. >>? >> i was as close to him as i am with you right now. >> you got to think, this is my guy. >> it's hard to think when you think you are sitting in effect to a killer. >> he never took his eyes off it. >> he and his son leave. we grab the cup off the table. my partner put gloves on, grabbed the straw, package it up. we disappear. >> the sample was sent for testing. the moment of truth. jerry not only the last burns' brother, he was the last possible suspect. den linger will never forget the moment he smoke to his contact at the crime lab. >> he said, that's your guy. >> he's the killer. >> he's the killer. >> the lab reported that the scientific probability was 100 billion-to-1. that meant the dna belongled to jerry burns and not anyone else on earth. finally, it was the culmination of a relentless decades-long investigation. but denlinger wasn't ready to make an arrest. there were too many questions that needed answers. >> it's time to go talk to him. he's not going to be ready, which is the best time to try to interview someone. >> so denlinger headed back to manchester. he pulled up to burns' place of business a little before noon. the door was opened. denlinger walked in. a hidden camera recorded everything. >> hello. >> get back up? . >> a lot of backup. we had no good expectation of what to expect from him, from his behavior. >> what's in his desk drawer? >> yes, correct. >> denlinger's camera in a travel mug. he introduced himself, set the mug down on his desk. >> he's petting his shop cat. >> cat's name. >> bella. >> he handed him a business card and got down to business. >> we're following up on an old case. it's a homicide that happened at westdale mall. >> then he described the computer sketch gopd from dna, someone called in with a up the and that's how his name came up. it wasn't true. den linger wanted to see how he'd react. >> that itself the picture we created. >> boy, it looks a lot different than i look in the mirror. do i look like that? >> i kind of think you do a little bit. not that we bothered to come up here and talk. >> burns remained calm and polite. he denied knowing michelle, but didn't say much more. >> you are holding the major ace card here. >> right. >> here's what science says. >> we have your dna at the crime scene and so we know you were there that night this happened. how would we get your dna at the crime scene there. >> i don't know, test it, see if it is. >> no, no, no, we did. how would it be there, jerry? >> i don't know. >> what happened that night? did you murder someone that night? >> test the dna. >> terry? test the dna. >> it wasn't the confession denlinger was hoping for. he didn't think it was a denial either. so 39 years to the day, jerry burns was cuffed and placed under arrest. >> you have the right to remain silent. anything you say can be used against you in a court of law. >> the charge was first degree murder, for jerry burns' daughter jennifer and brother donald, the news was a gut pun palm beach, impossible to comprehand. >> it almost seems like a dream that it wasn't really happening, it wasn't really true. >> could you believe it? >> no, my brother said dad's been arrested for murder, just like who? i was so in disbelief. >> the arrest just didn't square with the image of a devoted father, the good kid brother that they've always known. they felt certain there was something wrong with that dna evidence. >> there is other stories out there where there is a mistake of dna found at crime scenes and there has been an explanation for why it's there. it doesn't mean whoever's dna it was is the person that committed the crime. >> there is nothing to substantiate when it came there, how it got there. >> today now you say this just cannot be right? >> no, it can't be right. >> jerry burps' family was convinced he was innocent, but prosecutors convince a jury he was guilty? >> coming up, a damming discovery. >> there were files found on mr. burns' computer. >> extreme pornography? >> i think it was described publicly deviant pornography. >> and the risk of relying on dna evidence. >> i taught fifth grade. i know how hard it is to teach somebody something. you have to repeat it over and over and over again. i am concerned about that. >> when "dateline" continues. continues >> what can i du with less asthma? with dupixent, i can du more.. catching my train... making moves... ♪♪ making a connection... a train connection. that's how you du more with dupixent, which helps prevent asthma attacks. dupixent is not for sudden breathing problems. it's an add-on-treatment for specific types of moderate-to-severe asthma that can improve lung function for better breathing in as little as two weeks. and can reduce, or even eliminate, oral steroids. and here's something important. dupixent can cause allergic reactions that can be severe. get help right away if you have rash, chest pain, worsening shortness of breath, tingling or numbness in your limbs. tell your doctor about new or worsening joint aches and pain, or a parasitic infection. don't change or stop asthma medicines, including steroids, without talking to your doctor. are you ready to du more with less asthma? 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>> blonde women was a search term that was used, yeah. >> the dechs attorney filed a motion to bar the computer evidence from the trial. >> it wasn't germane to the case. this is -- material was found on mr. burns' computer 39 years after the crime. >> in a pretrial hearing, the judge agreed, dealing a blow to the state's case. which boiled down to a single piece of evidence against jerry burns -- that dna match. >> good morning, ladies and gentlemen of the jury -- >> the trial began in february, 2020. michelle's sister janelle and her husband john traveled from their florida home to attend, determined to see it through to the end. >> every day. if the jury has there, we'll be there. >> you examined the drafts -- >> the prosecution put the detective on the stand to tell jurors the police followed sound practices when they handled michelle's clothing. >> we wore rubber gloves, for one thing. we tried not to disturb the clothing items, just get a quick look at them and then reinsert them back in their original packaging. >> dna analyst linda sauer, since retired, testified the dna collected from that evidence could only belong to one person. >> the probability of finding two unrelated individuals is so small that it can be discounted. >> but the defense attorney wasn't rolling over for the state's dna case. >> jerry lynn burns is not guilty of the killing of michelle martino. >> the defense attorney went after the cops for the way they handled the evidence over four decades. he argued key items like michelle's dress were jumbled up with her other clothing, tainting them forever. >> when you opened up the original packaging of the dress, the panties and the panty hose, were the items all bundled together? >> as far as i recollect they were, yes. >> there was another reason to question the prosecution, the defense attorney said -- something called dna transfer. >> trace dna -- >> he quizzed his own expert witness. >> is it, dr. spence, a plausible explanation that the dna of jerry burns found on the dress or on the gear shift could have come about by a transfer? >> yes, that's a distinct possibility. >> the defense's dna expert told the court burns might have left his dna at the mall innocently on a door or a bench. after all, he told investigators that he had visited the mall. >> jerry burns' dna -- >> jerry burns, the defense argued, was a victim of coincidence and sloppy police work. >> ladies and gentlemen, the evidence has been submitted to you. >> after eight days of testimony, the jury got the case. when it goes out to the jury, what are you thinking? >> i mean, we're hoping for the best. if he wasn't guilty, great, we have dad home. if he was guilty it metropolitan more work, fighting for him. >> janelle was worried before a different reason. she knew the prosecution's case, the dna testing, the genetic genealogy was complicated, dense with data. >> i taught fifth grade. i know how hard it is to teach somebody something. you have to repeat it over and over and over again. i'm concerned about that. >> thank you. >> as it turned out, the jury reached a quick verdict. judge hoover read the decision aloud. >> we, the jury, find the defendant, jerry lynn burns, guilty of the charge of murder in the first degree. >> how did he take it, the verdict? >> i think he was shock, too. he was very much expecting to come home. >> don, you're in court, the verdict? >> i was surprised at the verdict. i had a hard time believing that the jury sat down and even reviewed the case. >> three hours. >> yeah. >> not even three. >> i couldn't believe they came back with the verdict they did. >> outside the court house, john and janelle were emotional. >> to finally have the closure on this and to actually know -- i wish my parents could be here to see this. >> we left cedar rapids, but cedar rapids never left us. >> i could feel the pressure of 40 years and countless police officers that had worked on this case. i felt like we as a team had finally done justice for the martinko family. >> burns was sentenced to life without parole. he is appealing his conviction. >> as we were looking through pictures, we realized that she wasn't part of that christmas, she wasn't part of that birth, she wasn't part of that party. we kept going deeper and deeper into the box trying to find where was michelle. she had missed everything. >> the family album goes on, but she's not in it. >> she's not in it. >> no, she's only in the old photos. a girl smiling out into a world of possibilities, stolen on a cold december night. that's all for this edition of "dateline." i'm craig melvin. thank you for watching. welcome to the show. i'm zerlina maxwell. russia is ramping up its attacks in eastern ukraine, and one of its military officials is warning the kremlin's goals may be wider than initially believed. meanwhile, here at home more city leaders are dropping their mask mandates. is that in line with what scientists recommend or even what most americans want? and florida democrats cried, sang, and screamed to delay republicans from passing a congressional map that wipes out