am trying a case, what drives me the most is the victims that i wanted to speak for them. i wanted to speak for helene. >> i just turned on the news. woman found murdered in denver, colorado. i just grabbed my son and screamed and cried. >> was it someone she worked with at the radio station, could it be the boyfriend that she just broke up with in december marks >> you are giving the detectives names of people? >> yes, we looked at everything. i was even like, where was ted bundy at that time? >> we have to look at every stone, every bubble. hundreds, thousands. >> she is driven. her tenacity is just remarkable. >> i knew i was going to find him. it was a competition between he and i. >> your heart is pounding like, oh my god, this is real. >> i said, i found him, i know who killed helene. hello and welcome to "dateline." helene brezinski lived by a simple philosophy, smile and make the best of everything. the budding journalist did just that as she started a internship in college radio. then, helene was murdered. this led detectives into the darkest corners of the criminal world before a ground breaking investigative tool helped to bring the secret to life. here is josh mankiewicz with "a promise to helene. " 40 years is a long time. that is 40 winters here in colorado, and countless snowfalls. it was on a day like this that a young woman disappeared. her name was helene, and helene had a friend named kimberly, a friend who kept her word. >> do you have any idea how many years you were signing up for when you made that promise? >> no. >> for those nearly 4 decades, kimberly latourette kept her promise. 40 years looking at faces, 40 years meeting with detectives, 40 years retracing helene's steps. >> when i make a promise and make a commitment, i follow through. >> helene never knew it, but she had another friend . >> you never met helene . do you feel like you know her? >> i do. i feel like i know her as well as i possibly could. >> shannon was 3 years old when helene disappeared and it was not until 2019 that she accepted a challenge. >> i wanted to win for helene. helene brezinski grew up as the baby daughter in a close-knit family of five in hamilton, massachusetts . >> everybody that met her like her company. >> janet was her older sister by nine years. >> that you did not treat her as like this annoying younger sibling? you guys were pretty tight? >> we were. she was my best buddy. she was a surprise, i think, to the family. she just brought sunshine in life to our household. >> i met her my freshman year of high school. she was a sophomore. we both were a part of a singing group called harmony. that is really where i got to know helene very well. >> she loved to sing ? >> yes, she loved to perform. >> i'm involved with harmony, musical group at regional. >> helene spoke about her school out for a classmate's local radio show. >> my philosophy in life, yeah, i have one. you should just be yourself and make the best of everything. smile. yeah, that is what i do all the time. >> here she is, smiling along with kimberly in their musical group. also joining in, kimberly's older brother, john. >> it was a real feeling of camaraderie, but also a dedication to excellence in our singing. >> he remembers the date camaraderie turned to something else. >> we started talking, and for me, it was an immediate spark. it was that fluttery feeling you have when you know you are talking to somebody that you realize you really like, immediately. >> they were just that in love. they were each other's first loves in high school, but very genuine. >> it did not last beyond high school, but john and kimberly both kept in touch with helene after graduation. helene attended wheaton college in massachusetts, where she sang in another group, the whea- tones. there she is in the back row with a black dress on. one more thing, as much as she loved her singing, helene had another passion, journalism . >> what you think would happen to her, where was she had it? >> to great things. i saw helene the christmas december of 1979 at church. she told me that she was going off to denver to do this internship to further her interests in journalism and she was very excited about it. >> helene arrived in january 1980 to begin that internship at a radio station in denver , a long way from home. fortunately, she had some relatives nearby. >> your family didn't worry about her going off to colorado, because she was not going to be alone and she was staying with your aunt and uncle? >> exactly. >> then, came that day, january 16th. helene had barely been there two weeks when she grabbed the bus from the radio station around 6:00 p.m. to go back to her aunt and uncles house . she had made the commute before without a problem. that night, helene pruszynski never made it home. >> my parents called me and said, they had just gotten a call from my aunt and uncle, this was maybe 10:00 at night. >> what did you think had happened? >> we had no idea. this was so unlike helene, something had to be wrong. >> the next morning, the news, none of it good, made its way back to massachusetts. >> that was the first thing that came up, hamilton woman found murdered in denver, colorado, and from there it was just horror and chaos. >> i went crazy. my son was 16 months old. i just grabbed my son and screamed, and cried, and i just couldn't believe it was happening, not to helene. >> that moment would launch a 40 year waste quest for justice to find helene's killer, and to learn what happened on that wintry night. >> detectives, family, and friends desperate for clues grasp at straws. who would want to harm helene? coming up. >> she gets off the bus and then she just disappears? >> she just disappeared. >> was the summer she worked with at the radio station? could it be the boyfriend she just broke up with in december? >> i thought i would be a suspect, actually. >> when "dateline" continues. when you see what it's really like when our skin touches wool... you see why we need downy free and gentle with no perfumes or dyes. it not only makes your clothes softer, it is gentle on your skin. it breathes life into your laundry. a slow network is no network for business. that's why more i choose comcast business. and now, we're introducing ultimate speed for business —our fastest plans yet. we're up to 12 times faster than verizon, at&t, and t-mobile. and existing customers could even get up to triple the speeds... at no additional cost. it's ultimate speed for ultimate business. don't miss out on our fastest speed plans yet! switch to comcast business and get started for $49.99 a month. plus, ask how to get up to an $800 prepaid card. call today! ♪ ♪ [ speaking minionese ] no. no. no. no. no. no. [ gasps ] [ chuckling ] good job, junior. way to go. [ chuckling ] [ speaking minionese ] in helene pruszynski's mall, massachusetts town of her family and friends sat stunned. she had been found murdered in a snowy feel in colorado. >> she was my first love, so she had a very special place in my heart. and what happened to her was so devastating. >> her wake was just horribly sad. i mean, no one could even speak. what could you say? >> you just go through the motions, and when it is all over, you sit and you still say, i can't believe this happened. >> murder changes everything. >> oh, it does. >> it changed the mood in rural douglas county, colorado. a high profile murder case will do that. >> as snow began to fall in the field of where young helene pruszynski was found, -- >> back in 1980, tony spurlock was a young deputy sheriff in colorado. today, he is the sheriff. >> what was douglas like then? >> douglas county was a completely rural community between colorado springs and denver. >> not a lot of homicides back then? >> maybe once every four years. >> investigators determined helene was last seen alive getting off that bus from work. >> from the bus driver me we know she got off that bus. from there-- >> nobody got off with her? she did not have trouble on the bus? >> there was no indication from witnesses she was in any distress or anyone was following her. >> she gets off the bus and then she just disappears? >> she just disappeared. >> helene's body was found the next day in a field nearly nine miles from that bus stop. she had been stabbed nine times. an autopsy revealed she was also rape. >> what did you learn from the body, the scene, the autopsy? >> a number of her clothes were missing. she was wearing a midsize winter jacket for colorado at that time and a scarf she was lying on her back. she had no defensive wounds, but she had wounds on her knees and lower leg area, which would tell us that she had either crawled on her knees at some point into that rough area of the grass, based upon her injuries. >> and she did not have defensive wounds me suggesting she was not fighting her attacker? she was trying to go along with him me maybe getting her to let her go to mark >> let some of us to believe that it was not a stranger, it must be somebody that she knew. >> but she did not know anybody there, did she? >> she did not know anybody, but she was working at a radio station. could it be somebody she turned down for a date or a ride or something that got angry? >> helene's friend, kimberly, started thinking about the man in helene's life. they were mostly just friends, but she passed their names to investigators anyway. >> you are giving the detectives names of people and saying, you need to check out this guy, this guy, this guy? >> yes. we said, could it be the boyfriend that she just broke up with in december? could it be-- i looked at my brother, i said, john, could it be you? >> of course, john was helene's ex-boyfriend veered as john worked through his own grief, it occurred to him, police might come knocking. >> i thought they would. i thought i would be a suspect, actually, but they never contacted me. >> that is because investigators quickly determined john was in massachusetts when the murder happened. in colorado, investigators focused on what little evidence they had. >> different world for law enforcement bagman. no surveillance cameras, no license plate readers, none of that. >> this was during the age of law enforcement where we still did not have dna. there was no technology that would help us track where she was at. >> there old-school police work did turn up something. a witness had seen a young man with medium build in his 20s or 30s, 5'9" or 5'10", he was standing by a car on the side of the road. it wasn't much. investigators wanted more from the witness. >> investigators put that person under hypnosis, and used a sketch artist to draw a rendition of the person that she saw standing next to a car on daniels park road, which would have been 100 yards or so away from where the body was found. >> networks, putting somebody under hypnosis? >> here's the thing, i've been doing this business for 40 years and i have heard where it worked and when he did not work. >> the result was this sketch. was it the killer, and would it lead anywhere? coming up. >> they are known as serial killers. according to law enforcement officials, there are at least 35 of them roaming the country now. >> a chilling new possibility. >> i was even like, where was ted bundy at that time? was he in colorado? >> a string of notorious killers on the loose. could one of them have committed this crime? >> these prolific serial killers certainly fit. >> it certainly fits. >> when "dateline" continues. but hey...nothing wrong with sticking it to the boss. ooooh, flo, you gonna take that? why would that concern me? because you're...the... aren't you the..? huh...we never actually discussed hierarchy. ok, why don't we just stick to letting dave know how much he can save when he bundles his home or auto with his boat or rv. wait, i thought jamie was the boss. [ laughter ] it's funny because i'm not boss material! nexgard® plus helps you protect your dog from fleas, ticks, heartworm disease, and more... all in one delicious, monthly, soft chew. use with caution in dogs with a history of seizures or neurologic disorders. nexgard® plus: the one you want for one-and-done protection. in the weeks after helene pruszynski's murder , police at last had a possible image of their suspect, except, it was not leading them any closer to her killer. >> you start throwing that sketch around and no one knows who it is. >> exactly. no one came forward and said, i know who that guy is. >> months went by and detectives just hit a dead end. >> it was clear that they had exhausted all of the leads by the wintertime of 1980 me going into ' 81, the case had gone cold. >> for the victim's family, there may be no greater frustration that having a loved one's case go cold. often, someone needs to play the role of the tireless advocate. even at only 26, kimberly realized that and made her promise. which was-- >> i saw helene's parents and i just promised them that i would not stop for as long as i was living, and doing everything in my power to find helene's killer. >> everything to kimberly meant constantly calling detectives, generating press coverage, anything to keep a laser focus on the case. >> i did not want to see her parents, or her sister, or her brother have to not only deal with just day-to-day living, take some of that burden off of them and for them to feel good that somebody was still actively working on it, and keeping that case alive. >> and then, in 1983, the case did seem to gain new life. throughout the 70s and early 80s, a number of serial killers had been grabbing headlines. >> we looked at every serial killer. i was even like, where was ted bundy at that time was he in colorado? we looked at every known serial killer that was active at that time to see if they could have possibly been in colorado. >> and then, there were these two men, henry lee lucas and oddest tool here they were drifters, rested and jailed in the early 80s and began telling law enforcement something astonishing, how they had killed more than 200 women in a dizzying spring across the country. >> prime analyst there have painstakingly recorded hundreds of dress, out of trouble, and method of killing in the lucas tool murder cases. >> that is murphy dennis reporting another pair for nbc nightly news. >> they are known as serial killers, and according to officials, there are at least 35 of them roaming the country now. >> and these two told police about one particular victim in colorado. >> they confessed to committing the murder of helene pruszynski. what was unique about them was 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 that work together, these prolific serial killers, that certainly fit? >> it certainly fit. >> it's pretty seductive when a couple of serial killers were on the hook for a lot of other murders confessed in your murder, because it would close a lot of cases if you can link them to these guys. >> right. obviously, this is awesome. we got a confession. >> colorado investigators headed to texas to interview lucas themselves. the detectives showed him a map and asked him to pinpoint where he and tool picked up helene. >> and we took her way out in the country, well, there's a bunch of rocks and stuff out there. she was stabbed to death, raped, covered up with a sheet , and some plywood. >> then, lucas added another detail. >> she was stabbed to death, and shot once i think in the head. >> who shot her? >> i shot her in the head. >> at that moment, they had a problem, helene was stabbed, not shots. to detectives, this confession was starting to sound phony. they dug deeper, looking into lucas and tool's long trail of arrest records. >> we could link them to other jurisdictions by other legal documents that could be authenticated, but it would be impossible for them to be in two places at one time. >> they were not in colorado at the time helene was killed? >> they were not in colorado at the time she was killed. >> i was about to confess to a murder they did not commit? what would be in it for them? >> they were becoming famous and they knew they would spend the rest of their lives in prison, if not on death row. >> so why not be the most prolific serial killers in the country? >> exactly. >> as for any other serial killers on the prowl back then, none could be placed in colorado at the time. ted bundy actually had spent time there in the late 70s, but he was behind bars in florida at the time of helene's murder . the serial killer leaves had dried up. >> was that disappointing when that did not pan out? >> that was disappointing. we knew at that point we were back at .0 with nothing to work on. >> it would not happen quickly, but over time, this case would go from .0, to 100 with a young detective up for a challenge. coming up-- >> what i focus on when i'm working a case, what drives me the most is the victims. i want to speak for them. >> a new investigator at a bold , new approach. >> you are talking about hundreds of names here. >> hundreds, thousands. having been a competitive athlete most of my life, i think really it was a competition between him and i. i knew i would find him. i wanted to win for helene. >> when "dateline" continues. and it began her family's touching story that is still going on today. vicki: childhood cancer, it's just hard. stacey passed on christmas day of 1986. there is no pain like losing a child, but saint jude gave us more years to love on her each day. marlo thomas: you can join the battle to save lives. for just $19 a month, you'll help us continue the lifesaving research and treatment these kids need now and in the future. jessica: i remember as a child, walking the halls of saint jude, and watching my sister fight for her life. we never imagined that we would come back. and then my son charlie was diagnosed with ewing's sarcoma. vicki: i'm thinking, we already had a catastrophic disease in our family. not my grandson too. marlo thomas: st. jude has helped push the overall childhood cancer survival rate from 20% when it opened to 80% today. join with your credit or debit card for only $19 a month, and we'll send you this saint jude t-shirt that you can proudly wear to show your support. jessica: for anybody that would give, the money is going towards research, and you are the reason my child is here today. charlie: i was declared-- this will be two years cancer free. but there's thousands and thousands of kids who need help. saint jude, how many lives they do save is just so many. marlo thomas: charlie's progress warms my heart, but memories of little angels like stacy are why we need your help. please become a saint jude partner in hope right now. [music playing] welcome back to "dateline." i'm andrea canning. helene pruszynski was found murdered outside of denver. police pursued everything, including two false confessions from two nestorius notorious serial killers. decades would pass before a young detective picked up the case and set her sights on a promising new suspect. back to josh mankiewicz with "a promise to helene." helene pruszynski's murder had become the textbook example of a cold case. in 1948, a ray of hope sprang up . it came from a somewhat newer textbook. the use of dna evidence had become a revolutionary tool in criminal investigations. douglas county detectives realized, there was dna from their suspect in evidence. >> there was body fluids on these pieces of materials or swabs from the autopsy that had not been tested. so, we were very excited at that time, because we had an abundance of dna evidence available to us. >> evidence that had been preserved, even though you are not testing for dna back then, no one was. >> know. and to this day, i give the credit to the karo colorado bureau of investigation crime scene that dna evidence had no idea what would be into the future, but they collected it, they properly stored it, and properly packaged it to where in 1998, we could open it up and scientists would say, that is perfect, let's use it. >> investigators were able to put that dna kit into the fbi's database of profiles. >> that is a very huge, lucky break. except, it does not match anybody in kotas. >> does not match to anyone. >> spurlock and his team were disappointed, so was kimberly, but always mindful of the, she made, caverly was not about the to let the case freeze up again. >> i would jump on it and shake the trees and i was never met poorly. i was always met with welcome arms by the colorado detectives. >> she was key in connecting us to other people that we felt were very important to the case. >> in 2004, kimberly was arranging a reunion concert of their singing group, harmony, to celebrate helene's birthday, when she had an idea . >> i said, it's time. we need to get this solved. let's fly out on the anniversary of helene's murder and retrace her steps in real- time. >> i mean, you know the detectives have done that before, probably right after the murder and probably a bunch of times since, what did you think you would get out of it that they had not done? >> create a media stir in the news, hoping that the killer would see us, would know that there were eyes still on the case, make a lot of noise. >> four high school friends of a young woman murdered 26 years ago say, there still hope their friend's killer will be found. >> the plan worked. they made all the local newscasts. >> we decided to do whatever we could to ensure this case is reopened and solved. >> may also set up a website about the case, hoping the killer might click on it and reveal his internet address. >> that was our hope, to get the worm to crawl out from under the rock. >> that did not happen, the worm stayed hidden. >> he did. >> in 2009, helene's brother died, then her mom and dad followed in 2012. sister, janet , was the only one left. >> you've settled into this life where you don't know. >> right. it was heartbreaking. >> by june 2019, helene had been dead almost 40 years, the coldest of colorado cases. that is when a new detective, shannon jensen, was assigned to the case. >> what i focus on when i am working on a case, what drives me the most is the victims. >> jensen had been a competitive rower at cal berkeley before she enrolled at the police academy and joint law enforcement. she got to know helene through all of the pictures and information in the case file and she was hoping to get to know someone else. >> what do you know about your unknown suspect? you know it is a man, you know he is between the ages of-- >> we don't know his age. we know the witness says he was in his early 20s, but ultimately, no one else saw him. >> detective jensen said, the key to all of this was the dna profile. she decided to consult with a genealogist and upload the suspect's profile into a web set website called ged match, a website people use to connect with relatives. >> absolutely. they allowed law enforcement to upload kits of dna, and that is matched with kits that opt in that want to assist law enforcement. >> so, jensen started looking with dna of anyone similar to that of the suspect. this is not just a matter of plugging jumbles of code into the computer, it is the equivalent of old fashion, she letter shoe leather detective work, but for the 21st century. that is because a similar dna profile is just another lead that needs running down. instead of knocking on doors, jensen was picking up the phone. she was asking for cooperation from possible distant matches. >> you are this disembodied voice on the phone saying, tell me about one of your relatives that might be a martyr, and i need you to help me and give up some personal information? >> yes. >> with a be willing to share their entire family history on the chance they were related to a murderer? it is a big ask. >> and i would contact these matches. they would give me their family trees and any family history they had, so that we could fill in for adoptions or unknown pregnancies. >> you are talking about hundreds of names. >> hundreds, thousands. the people that spoke to me about it said, if this is someone in my family that did this, they should be arrested for the crime. there should be justice for this young victim. >> what's it like for you, knowing you are pursuing this cipher? >> having been a competitive athlete multiple most of my life, i think it was a competition between him and i. i knew i would find him. i wanted to win for helene. >> by the fall of 2013, detective jensen seem to be making progress after speaking with context through the database and building those family trees, she had found a woman whose dna was so close to that of the killer, she might be a first cousin. there was just one problem. >> that first cousin didn't really know her family. the family wasn't close. >> with there be any way to fill out that possibly critical family tree? because in put jensen in touch with another cousin. >> when you talked to that woman you think, this is it, we are getting close? >> yeah, i knew. this is it, i am on the right track and i will figure out who he is real soon. >> coming up.>> she's like, i know who did it. i like him who did what? she's like i know who the killer is for helene. >> the beer mug that just might feel the case. >> i was convinced very quickly by their determination. >> i mean the heart is pounding. this is it, this is the guy. when "dateline" continues. you can save 5% every day. you got this. and we got you. i'll be honest. by the end of the day, my floors...yeesh. but who has the time to clean? that's why i love my swiffer wetjet. it's a quick and easy way to get my floors clean. wetjet absorbs and locks grime deep inside. look at that! swiffer wetjet. stuck at the dmv, and i think i'm late on my car insurance. good thing the general gives you a break with flexible payment options. let's get you a break while you wait. what is this place? this is our dmvip. vending machine charcuterie? for a great low rate, go with the general. i am richard louis with the news update. the supreme court upheld a federal law that prohibits people subjected to restraining orders for domestic violence for owning firearms. the decision is a step back from the recent trend of raleigh favoring gun rights. judge eileen cannon held a hearing friday on donald trump's motion to dismiss the classified documents indictment case against him and his lawyers argued that jack smith's appointment as special counsel was unconstitutional. as election date nears, there remains no trial date in sight. for now, back to "dateline." kimberly latourette had spent years helping to determine to help solve her friend's helene murder. she was nothing but resolute. that said, fate tends to keep its own schedule. kimberly, with a husband and kids, learned that in 2010. >> my older one went off to college, the same week my husband died, his dad, and my younger one was 15, and fell into a deep depression. i did not know how depressed until he went off to college at northwestern university and ended up taking his own life. >> it was a one-two punch that would have crushed a lot of people. despite that, kimberly never lost sight of her friend, helene. >> certainly no one would blame you for saying, i still want to solve helene's murder, i still want to help the police, but that is on the back burner now . i have other things to deal with. >> or maybe that is when i became obsessed with "dateline" episodes. any tiny thing i could pick up on an episode, i would immediately call douglas county or the colorado bureau of investigation and say, did you think of this, did you look at that? >> at her desk in colorado, shannon jensen was asking some questions of her own, with a computer screen and telephone as her tools. and she had tracked down a promising lead. she spoke with someone whose dna profile was close enough to that of the killer, that they were likely cousins. that cousin told jensen about two men who had been estranged from her family for years. >> there were two brothers. essentially, i had to look at both of them. >> and as she started digging, something stood out about one of the brothers. >> outcomes the criminal history for curtis allen right. >> curtis wright was convicted of rape in the late 70s. douglas county, colorado, where helene pruszynski was murdered , it's all fit. >> he was how old at that point? >> 21 when he was paroled here. >> same age as helene. >> yeah. >> it was time to tell lieutenant tony, then boss of the cold case. >> she was like, i know who did it, i know who the killer is for helene. i am like, no you don't. >> he knew all about the investigative dead ends in the case. he had seen plenty of them over the years. >> i'm like, how do you know you do? and she understood the dna, the genealogy, i didn't. she had to explain it. then, there is still that little bit of doubt, do i go upstairs, don't i? so, i did. >> they made the walk upstairs to face the sheriff. >> and they said, we believe we've got him to me this is the guy. >> you've been on the business end of a few other this is the guy conversations where it did not pan out? >> i was. >> detective jensen laid out her case, two brothers, only one in colorado at the time of the murder. and there was another thing, as jensen dug through white's's criminal history, she discovered an old mug shot from 1998. remember that initial witness sketch, drawn with the help of a hypnotist? >> you get that booking photo from 1998 in florida, and it looks like the sketch, doesn't it? >> it looks like one of the sketches, pretty remarkably. >> those two you could lay them over each other. it was the mustache, the hair, the eyes. it was so eerily positive. >> the sheriff was sold. >> i was convinced very quickly by their determination and i think also their confidence in what they had learned through this genealogy that this is the one we needed to after. >> i mean, the heart is pounding like oh my god, this is real. this is the guy. >> they needed to find curtis might and tracked him to florida, where he had been living under a new name, james curtis clapton. >> he became james curtis clanton and went on with his life, got married, had a child, built a career for himself, and went on with his life as if nothing happened. >> and stayed out of trouble? >> yeah, pretty much. >> douglas county detectives went to florida to watch him. >> he is living in a trailer on somebody's property. we see his van. he had a white van with a shark on the side of it. we see him, okay, we got his house, the van. >> when you are down there in surveilling this guy, the first time you see him and think, that is helene's murderer right there, getting in his truck?>> yes. >> they surveiled the newly minted mr. clanton as he drove to a local bar to grab a beer. and, investigators asked the bar's owner to save those mugs. >> he grabbed them, put them in bags for us and met us at the back door and handed them to us. yes, sir, three beer mugs. >> the detectives the mugs back to colorado. >> do you say to the dna lab, this is it, step on it? >> they knew it, colorado bureau of investigation had been working on this case since 1980. >> everyone waited until finally shannon jensen got the call. >> the lab tech said, it is a match. one of them had your suspect's dna sample and it matched the semen left on the coat. >> what is that like? >> i don't know if i can describe what it is like. it is extremely rewarding. >> and then the bad news, the statue of limitations had expired on the rape, meaning, clanton could admit to that with no consequence and denied the murder. to make their case stronger, detectives needed to get clanton to talk with them. so, the team came up with a strategy. >> the plan was to talk to mr. clanton, see if we could get him to come down voluntarily to talk to us and kind of slow pay play into why we were there. the technique we used was that his social security number had been used in a large identity theft case. >> the officers wore body cameras. >> the mind voluntarily coming down to the sheriff's office at union county just to talk for 8 video recorded interview for couple of minutes? >> after four decades, what would he have to say? coming up-- >> i lived in colorado many, many years. >> detectives are on the hunt for answers. >> we do care about a young woman in colorado in 1980. we want to show you a picture of her and see if you recognize her. >> would helene get justice at last? >> i lost it. i really , really freaked out. >> i was paralyzed. i cannot even breathe. >> when "dateline" continues. but this is my story. 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[traffic noises] so get allstate, save money on auto insurance and be protected from mayhem. yeah, like me. ♪♪ colorado investigators were finally in the room with the man who might have killed helene pruszynski more than 40 years ago. james clanton thought he was there to answer questions about an identity theft ring. >> have you ever had lived or done business in colorado that we are not aware of? >> i lived in colorado, many, many years. >> okay, that is helpful. when was that, approximately? >> 1979, 1980. >> that was important, clanton was now on tape saying, he had been in colorado when helene was killed . it was time to change the subject. >> we do care about a young woman in colorado in 1980. i want to show you a picture of her and see if you recognize her. >> no, sir. and i think i want an attorney now. you are accusing me of something else, i know. >> clanton stopped speaking with investigators. it didn't matter, his dna spoke for itself. >> we do have a warrant for your arrest. >> for what? >> first-degree murder and kidnapping. >> you got the wrong guy. >> we actually have your dna in her and on her. >> later that day, janet pruszynski looked down and saw a colorado number on her phone . it was the sheriff. statement he said, we want to tell you that we have found a murderer. so, i lost it. they were saying that, i really, really freaked out. it was the realization that after 40 years, there would be justice served and it was just as hard to comprehend. >> because it is a relief, but also a reliving? >> exactly. >> lieutenant tommy barela began exporting clanton back to colorado. as they spoke, the detective began gaining his trust. >> you are building a rapport with this guy? >> kind of, yeah, i am just a personable guy. >> their suspect had clammed up in the interview room, and then suddenly seemed to have a change of heart. >> he wants to talk. >> he wants to talk. my gosh, you've got to let them talk. >> as they drove to the airport, barela grabbed his iphone and pressed record. >> my name is lieutenant tommy barela. jim has advised me he'd like to talk to me about the crimes he is being accused of. >> clanton told barela he was not surprised when detectives asked him about helene. >> because i knew that was going to come up and get me one day. i did it. >> you did what? >> i killed the girl they are accusing me of killing. >> at that moment, i was like, holy crap! pinch me, he just admitted it. like, oh my god. >> clanton laid out the details of that cold day in january 1980, how he had seen helene getting off the bus and forced her into his car . >> i put my arm around her and had a knife in my hand and showed it to her. >> did she say anything? >> she said, i'll go. >> helene, he said, was cooperative, which explained the lack of defensive wounds on her body. he confirmed that he raped and stabbed her multiple times, then left her in that snowy field . >> the fact that she was alive and on that bus is the only reason he kidnapped, raped, and murdered her . >> and he is going to pay for that. >> yes. >> and clanton had one more thing to say. he claimed his life of crime could have been worse, he says, it wasn't, because something about helene had haunted him. >> you know, i got a conscious and in my mind, i had actually took the step over to becoming a serial killer with helene , and i couldn't, because of who she was and so, i'm a serial killer at one. >> kimberly, who made some calls trying to keep the case alive, now received a call herself. >> i cannot even breathe. it wasn't, it wasn't jumping for joy, it wasn't crying, it was just pure shock. i was paralyzed. >> after 40 years, the end came quickly. there was no trial. james clanton pleaded guilty to helene's murder. many of her friends and family traveled to colorado in july 2020 to speak remotely at his sentencing hearing. >> helene was never forgotten . her spirit never died. >> mr. clanton, i sentence you to a sentence in the department of corrections for the rest of your natural life. >> and then, they had a reunion, of sorts, with some of the many investigators who had worked helene's case over the years. >> it was amazing to sit across the table from them all and just soak in who helene pruszynski was in their mind. >> when we last spoke, janet said, she still thinks about her baby sister every day. >> you are doing okay? you have grandchildren now? >> two grandchildren, yes, and one of them was born on helene's birthday, my granddaughter. >> what do you tell them about helene? >> we have pictures of helene in the house. she's only 5, so i have not said too much yet, but she will know a lot about helene. >> you finally have justice for helene, her family, all the victims left behind. >> it's kind of why you got into police work, isn't it? >> it is. >> after a 40 year crusade for answers to me it was the truth that connected two women. the detective who took on a quest, and the friend who never forgot. >> helene needed to be heard. she needed people to know what happened to her, so she is not alone anymore. that's all for this edition of "dateline." i'm andrea canning, thank you for watching. for watching.