day. >> that's all for this edition of "dateline." i'm craig melvin. thank you for watching. i'm craig melvin. >> i'm natalie morales. >> and this is "dateline." i fell to the floor. i just remember like, "she's dead. she's dead!" and i was so confused. i was like, "what's going on? what -- what happened?" >> a small texas town, two super close friends, and a summer night in the park. >> they have this lookout, and you could see the harbor bridge lit up. it's really pretty when the stars are out. >> it was the next morning that they found them. >> i could see two girls laying

there. it was horrifying. there was duct tape on their mouths, on their hands. >> a mystifying scene. >> the only thing we have are cigarette butts and suspicion. >> dna would point one way. >> he's, like, serge, you got to take a look at this. >> a bombshell message would point another. >> i read the letter and immediately knew this was something very important. >> a twisted trail leading to a sinister suspect. >> takes a special kind of mind that wants to do something like that. >> to crack a case this convoluted, it might just take a miracle. >> that was extraordinary. >> i just couldn't believe it. >> welcome to "dateline." two young women were discovered in a park bound and gagged, both were sexually assaulted and shot in the head. one died.

but the other miraculously was still alive. some wondered, could a secret relationship have been the motive for murder? here's josh mankiewicz with "a texas twist." >> reporter: named for the body of christ, corpus christi sits on the texas gulf coast. and just east of the bay is a park known for bird watching. that's what chris seymour was doing there when he came across something very unnatural. >> to me, it just looked like a pile of debris, to be honest. and then he looked and he said, "oh, my god, it's two bodies." >> reporter: a crime so shocking that years later, they're still talking about it. >> i can't even imagine what was in that person's mind that evoked his violence, his rage. >> reporter: two young women. who wanted them dead? and why? >> it was a true whodunit type

murder. >> reporter: and along with who and why was the question of why here? >> this was definitely something that we weren't used to or accustomed to in our town. >> reporter: this part of texas isn't exactly ground zero for murder. it's known more for roping, riding, and friday night lights. here, life is pretty simple, as are the values its people hold dear, like friendship, family, community. this is where 19-year-old mollie olgin grew up. >> tell me a little bit about what she was like. >> she was really funny. she had a weird sense of humor. always smiling, laughing. >> she's just a really good person. >> reporter: megan olgin was mollie's older sister. just two years apart, they were, says megan, fiercely competitive.

>> she was really smart, which i was always kind of jealous -- because math came so easy to her. all the subjects came easy to her. she didn't even have to study, try, nothing. >> reporter: mollie also played drums in the high school band. but her friends, brooke ostrom and stephanie chasak, say that what mollie really loved was cruising down the highway singing along to bands like the spice girls. that's mollie behind the wheel. >> she loved her car a lot. i remember one night she decided, "i'm gonna name my car jabar." and after that, she called her car jabar mccar. and it was the funniest thing, for no reason. >> reporter: smart, funny, and a car owner, all of which made for one very popular teen. >> she had a lot of friends. >> yes. >> oh, yeah. >> a lot of friends. >> she never let anybody leave from hanging out with her without giving them a hug. >> and saying, "i love you." >> ever.

>> reporter: which was certainly true when it came to the newest member of mollie's unusually large posse of friends, 18-year-old kristene chapa. >> could you tell they really liked each other? >> yeah. >> yeah. mollie talked about her a lot. >> reporter: kristene lived in a neighboring town where she was earning a reputation as a softball superstar. >> kristene was a softball icon for this town. >> reporter: brittany selby was kristene's close friend. >> she was, like, the comic relief in our little group of friends. >> reporter: brittany says kristene's sense of humor was a perfect match for mollie's. >> mollie definitely brought out kristene's crazy side. it was never -- never a dull moment with those two. >> reporter: but for this group of girls, "crazy" and "dull" were relative terms. >> we were not the party kids. we never drank or anything like that. we would go to taco bell. we would go to coffee shops. and we would go to parks.

>> reporter: which is exactly what mollie and kristene decided to do on a warm summer night back in june of 2012. their destination, violet andrews park. >> that place seem safe to you? >> yeah, it did. >> all the parks did. >> we would go at night all the time. >> reporter: before heading out, the two called brittany, asking if she wanted to join them. brittany took a pass. >> they had asked me to go, but i had a volleyball game the next morning. so i wasn't able to. >> reporter: it was a decision that still haunts her. >> i just know -- because they, like -- you know, they called me that night. i'm like if i was there -- >> reporter: the next morning, chris and stan seymour were strolling through violet andrews park. >> we started looking around for birds in general. didn't see a thing. this place was as quiet as we'd ever seen it. >> reporter: and that's when, just below one of the overlooks, they made their terrible discovery. in the tall beach grass lay the

bodies of two young women. >> it just looked like they had both been molested or mauled. >> we didn't know if they were alive or -- or -- or dead. we had no idea. >> reporter: the seymours ran for help. >> portland 911, what's the location of your emergency? >> we've got two dead bodies down here. >> are they male or female? >> two females. >> reporter: first responder travis weisman had never seen anything like it. >> it was horrifying. there is blood. i can see that the clothes are off both girls. there was duct tape on -- on their mouths, on their hands. you could see they were clearly bound. >> reporter: duct tape also covered their eyes. and each girl had been shot in the back of the head. >> i went and checked the pulse on the first girl, i could feel her body was cold and didn't feel a pulse. >> reporter: and then something no one expected. >> i went to reach for the second girl, and that's when she started to sit up and moan. >> it looked so hopeless.

and to think that one was alive was just a miracle. >> reporter: which girl had survived? could doctors keep her alive? and what story could she tell? the questions were just beginning. >> one victim surviving. the first surprise in a case teeming with twists. investigators focus on one particular clue. coming up -- >> sometimes that can suggest somebody who knows the victim. >> yes. >> when "dateline" continues. ♪ ♪ protect your pet with the #1 name in flea and tick protection. frontline plus. trusted by vets for nearly 20 years.

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2012, news of a double shooting in one of the parks began to slowly spread throughout the texas gulf coast. stephanie chasak and brooke ostrom learned about it on facebook. >> didn't say who it was. didn't say male or female or anything along those lines. >> you didn't think it would be anybody you knew. >> i didn't think it would be anybody i knew. >> reporter: brittany selby tried to call both kristene and mollie. >> neither one of them is picking up. so that's when i started to get worried. >> reporter: kristene's parents, grace and larry chapa, were worried, too. grace had been pacing the floor ever since she discovered kristene hadn't come home the night before. >> that's unusual. >> that was very unusual. >> by now, how many times have

you called your daughter? >> i would say about four or five times i called her. i even told her, "i'm gonna call the police if you don't call me right now." >> reporter: which is just what grace did. that's when she learned kristene had been hurt. but the officer wouldn't say much else, only that grace needed to get to memorial hospital. >> he doesn't tell you what happened? >> no. he doesn't know what happened. >> reporter: it was only after arriving at the hospital that the chapas learned kristene had been shot. but they still didn't know if kristene was alive or dead. >> the nurse walks in and tells us one girl died and one girl is on the second floor. and we need to identify her. >> and they don't know who died and who lived? >> no. >> reporter: it was up to the chapas to identify the survivor. >> you couldn't go? >> i couldn't go. i couldn't do it. >> reporter: so grace assigned her eldest daughter that grim task. >> so the best you're gonna hope for here is that it's your daughter.

but she's -- already pretty seriously hurt. >> she's hurt. yes. >> reporter: for the chapas, the wait was excruciating. and then their daughter returned with the news they had been praying for. >> she comes back down. and she tells me, "mom, it's kris." >> reporter: family and friends took turns at kristene's bedside wondering if she would ever regain consciousness. >> i was talking to her and telling her that i was there and that we loved her. >> how'd she look? >> it was bad. it was so bad that you couldn't even -- you didn't know it was her. >> reporter: the bullet had entered the right side of kristene chapa's head and shattered, destroying some of her brain tissue. during a lengthy surgery, doctors decided not to try to retrieve the bullet fragments. but at least kristene was still alive. by now, the other victim had been identified as mollie olgin. and news of mollie's death had reached her family.

>> i was in shock. i remember crying really hard, and i was throwing stuff in my room because it just didn't seem real to me. >> how were your parents? >> really emotional. i had never seen my dad cry. they took it really hard. >> reporter: so did mollie's friends, stephanie and brooke. >> i just remember like, "she's dead, she's dead." and everyone's like, "who's dead?" and i said, "mollie." >> reporter: over the next few days, neighbors here began asking the same question, who had pulled the trigger and why? finding those answers fell to portland, texas, police detective roland chavez. >> mollie can't give us any information, and kristene's in the hospital and she can't give us any information. >> at that point, not even clear whether kristene's -- >> gonna survive. >> right? >> yeah. >> reporter: tips were coming in. someone said they saw a white car speeding from the park the night of the shootings.

that lead nowhere. so chavez and his team focused on the crime scene. there was no murder weapon. they did find two spent .45 caliber casings. >> reporter: and near an observation deck just thirty feet away from where mollie and kristene were discovered, police found an empty monster energy drink can and five cigarette butts. >> and the girls didn't smoke? >> the girls did not smoke. >> reporter: chavez sent all that for dna testing. as for the duct tape used to cover the girls' eyes, chavez thought maybe that was itself a clue. >> sometimes that can suggest somebody who knows the victim. didn't wanna see them. >> yes, uh-huh. >> far as you know, either of them have any enemies? >> no. that's what was so confusing. >> everyone loved them, you know. >> reporter: and that's probably why they were all so discreet when it came to kristene and mollie. now, as a murder investigation

began, friends revealed something that not many knew. >> they began to tell us they were in a -- in a relationship. >> these weren't just two friends. they were dating. >> yes. >> reporter: that had many here wondering if a romance that was hidden from many might have in some way been a motive for the attack. >> conceivable that this was some kind of hate crime? >> i mean, i'd be lying if i said that thought didn't cross through my mind. >> reporter: three days later came news from the hospital. kristene chapa had regained consciousness. >> we're hoping now we're gonna be able to really get the ball rolling. >> reporter: the story kristene eventually shared with police provided intriguing clues about the identity of her attacker. and it's a story kristene will also share with you. coming up -- kristene harrowing account. >> first we asked her, did you know the person that did this? >> when "dateline" continues. discover card.

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>> reporter: larry and grace chapa kept a sleepless vigil over their daughter kristene as she lay in the icu, hovering somewhere between life and death. the 18-year-old had been shot in the head and left outside for more than eight hours. somehow, she'd survived. then, just days after her brain surgery, kristene again defied the odds and began to stir. >> that's an incredible little girl here. i'm -- i'm telling you, she is something else. >> we asked her questions. she would squeeze our hand. >> reporter: that must've been a wonderful thing to see. >> it was. >> reporter: for police, the pressure to find the shooter was intense. detective roland chavez hoped kristene, now conscious, would be playing a big part in that. but kristene still could not speak. >> it was either a squeeze of

the hand, and then the blinking of the eyes. >> reporter: so chavez kept his questions simple. >> the first thing we asked her, of course, is "did you know the person that did this?" and she said, "no." >> reporter: and how tall was he? >> she'd described him as about 5'8", 5'9." >> reporter: within the first two weeks of her recovery, kristene helped police draw this sketch of the man who shot her. she said he smelled of cigarettes, which made chavez think about those cigarette butts found at the crime scene. he asked that the dna tests on those be put on the fast track. >> one of the things that kristene was also able to give us was that the assailant wore gloves, and under armour gloves specifically. >> reporter: she saw the logo? >> yes. and she was a softball player. so she's saying under armour gloves, then under armour gloves is probably exactly what we're looking for. >> reporter: but during those sessions with kristene, chavez wasn't the only one asking questions. kristene struggled to ask a few

of her own, tough ones. was kristene asking you about mollie? >> she did. we -- we did not initially give her any of that information. >> reporter: both chavez and kristene's parents were afraid that the truth about mollie would upset kristene and maybe jeopardize her recovery. >> i would just tell her mollie's got -- got sent to another hospital. >> reporter: of course, kristene persisted. and eventually everyone decided she deserved to know mollie's fate. family and doctors assembled in kristene's room when detective chavez revealed the truth. >> she was distraught and crying and -- and i told her, you know, "i just -- i need you to stay strong so that you can help us, and we're gonna catch him." and so she did. >> reporter: as the days passed, kristene's communication skills steadily improved, enabling her to share with police more details of that horrible night.

>> it's supposed to be peaceful and safe. >> reporter: we wanted to hear her story, too. you look great, and it's great to see you. >> thank you. >> reporter: kristene began by describing her relationship with mollie. >> i met mollie at the mall. >> reporter: was there some chemistry right from the beginning? >> oh, there was. we were both very sarcastic, and we would just amuse each other and make each other laugh a lot. >> reporter: six months later, the two had become a serious couple. then came that june night in the park. why'd you go to the park that night? >> well, because we had missed our movie and so we were kind of driving around and just trying to figure out what to do. >> reporter: when they got there, kristene said she and mollie walked to one of the overlooks. >> we weren't even there for five minutes when we ended up seeing, like, this guy walk by. i got a -- this weird feeling and we wanted to hurry up and get out of there. and the next thing you know, he's right there on mollie's side with a gun. >> reporter: she said the man

then forced the two girls down a steep embankment and into the tall beach grass below. and she recalled the odd way he referred to them both. >> he called mollie "girl number one" and i was "girl number two." >> reporter: and he referred to you that way, by numbers, all the way through it? >> he did. >> reporter: what'd you say to him? >> i asked him if he was going to take us anywhere, and he said, no, this was going to be quick and easy. i could feel my heart beating so fast. i'm like, "man, i want my mom." and that's when i'm just like praying, "please god. don't -- don't let -- don't let me die. please." >> reporter: mollie say anything? >> we both asked each other if we were okay. and that was the last thing we asked, we both asked each other. >> reporter: that's when kristene says she was raped. but the ordeal wasn't over. >> he had the gun pointed at us still, and he made me put duct take -- duct tape over mollie's mouth and her eyes, and i had to

do the same to myself. i was already at the stage, like, "i'm gonna die." like, "this is it." and i hear the gun go off. and then i went black. and, like, everything went black. >> reporter: kristene's remarkable physical recovery turned out to be the easier part. >> i come out here for the anniversary of the shooting, for mollie's birthday, and, like, for the day we met. >> reporter: this is not a painful place to return to? >> it's not painful. i guess i just kind of feel closer to her, i guess, because it's the last place i saw her at. >> reporter: rehab helped distract kristene from her sadness. so did working with police to find mollie's killer. >> kristene was kind of our inspiration. seeing how hard she was working just made us continue to work even har -- even that much harder for her. >> reporter: it wasn't for lack of hard work, but police had to face the truth, the investigation had stalled.

at this point it sounds like you're kind of nowhere. >> yeah. >> reporter: and then, the dna tests of the cigarette butts and the drink can came back from the lab. and that changes everything. >> yes. coming up, a mysterious message rocks the case. >> the letter is written from the perspective of a hit man who has been hired to kill the surviving victim in this case, kristene chapa. >> when "dateline" continues. er) ...and told people about geico... (harmonica interrupts) how they could save 15% or more by... (harmonica interrupts) ...by just calling or going online to geico.com. (harmonica interrupts) (sighs and chuckles) sorry, are you gonna... (harmonica interrupts) everytime. geico. 15 minutes could save you 15% or more on car insurance.

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i'm dara brown with the hour's top stories. protests around the country on saturday against the trump administration immigration policy that has ripped apart families. though the president has signed an order ending the policy, more than 2,000 children remain separated from their parents. more than a dozen u.s. intelligence officials tell nbc news that north korea appears to be pushing ahead with its nuclear program at multiple sites in recent months. the white house has declined to comment. now, back to "dateline." welcome back. i'm craig melvin. christine chappia told a harrowing tale of being raped at gunpoint by a man she never met. she remembered her assailant was wearing under armour gloves. was this a detail that could help investigators unlock the mystery? here again is josh mankiewicz with "a texas twist."

>> reporter: day by day, inch by inch, kristene chapa walked a steady, if uneven, road to recovery. >> i couldn't move my left side. i couldn't move my hand or my arm, my leg. i had to relearn to swallow. >> you don't give up, do you? >> i don't. i try to stay motivated. >> reporter: so did detective roland chavez. he, too, was making progress. the cigarette butts and drink can, collected from the crime scene, had just given him his first major break in the case. >> what did the dna show? >> the dna showed that it returned to dylan spellman. >> reporter: who was dylan spellman? police learned he lived just three blocks from the crime scene. and chavez also noticed a striking resemblence to that sketch kristene had helped police draw of the gunman. >> we start trying to get background on dylan spellman. >> reporter: some quick computer searches revealed spellman had a

criminal past. >> dylan spellman had just been convicted of a violent crime. >> yes. >> on an armed robbery in in nevada. >> yeah. >> reporter: that nevada armed robbery occurred in 2010, a year and a half before the shootings. spellman and some accomplices broke into a home in a las vegas suburb and held a family hostage before robbing them and taking off. >> anybody get killed? >> no. >> reporter: and at the time of the shootings in 2012, dylan spellman was in the corpus christi area, awaiting sentencing for the nevada armed robbery. >> he had been sent here to -- to stay with a friend. >> reporter: what intrigued chavez were some unusual similarities between the nevada crime and the shootings in texas. >> as we started going through that case file, we started seeing more and more things that are lining up with what we're looking at. >> for example? >> the use of numbers. >> reporter: remember, kristene had said the shooter referred to

her and mollie as "girl one" and "girl two." >> he used numbers in that other crime? >> yes. >> they referred to each other by number in that particular crime. >> reporter: the similarities between the two crimes didn't end there. >> in the nevada home invasion, were the victims bound? >> yes, they were. >> he's gotta be number one on the list at this point. >> he -- he definitely jumped to the -- to the top. >> reporter: by that time, dylan spellman had already returned to nevada to begin serving his three-year sentence. so chavez hopped a plane to las vegas, hoping to hear what mr. spellman might reveal about his brief stay in texas. spellman admitted he was in the park the night of the shootings. but he denied being anywhere near the area where the girls were found. >> he said he was never on the deck. well, we've got dna on the cigarette butts that prove otherwise. >> why lie about that unless you're involved in the crime? >> sure. so, i mean, it -- that definitely raised more suspicion. >> reporter: chavez then told

spellman police found his dna just 30 feet from where the girls were shot. that's when he says spellman's demeanor changed. >> he asked me, you know, "what -- what -- what are the consequences?" and i said, "well, in texas, i said, you know this is a death penalty kind of case." >> reporter: and then dylan spellman asked about a deal. >> normally any person that's innocent isn't gonna ask for a deal. you're gonna profess your innocence. and he wasn't. >> now i'm thinking, "this is my guy." >> reporter: so chavez asked spellman to take a polygraph and spellman agreed. >> and how does he do? >> he fails. >> reporter: time for handcuffs, you're thinking? not quite yet. chavez could put dylan spellman at the crime scene, but still had no way of tying him directly to the shootings. >> we have no gun. we have no usable prints. the only thing we have are cigarette butts, monster can, and suspicion.

>> reporter: it didn't help that chavez's one eyewitness to the shootings could not identify spellman from a photo lineup. >> it was very hard because the suspects all looked the same. >> reporter: and then there was the matter of mr. spellman's height. >> he's big. >> he's, what, 6'8"? >> 6'8". >> reporter: remember, kristene said the shooter was quite a bit shorter than that. 5'8", maybe 5'9". >> for me, it -- it was always the -- the difficulty of -- of getting over the size. >> reporter: so chavez and his team regrouped. >> we began getting cell phone records for him, getting hair samples or, anything off the duct tape, anything off of the girls' clothing, anything that would be able to attach dylan spellman to them. >> does any of that lead anywhere? >> no, unfortunately it didn't. >> reporter: two years passed. the case grew so cold that chavez's chief decided to give it to a new detective, hoping he might have better luck finding

the missing pieces. detective aaron veuleman had been working the case. and now he took the lead. >> what we first wanted to do was expand the scope of the crime scene search because we -- there was one crucial piece of evidence that we didn't have at that point, which was a murder weapon. >> reporter: veulman hoped the murder weapon might definitively link spellman to the shootings. >> what'd that turn up? >> we didn't find anything. nothing of value. >> so you're back to kinda nowhere. >> that's right. >> and then? >> we received a phone call from the investigators at the sinton police department. >> reporter: those investigators in the neighboring town of sinton had just been given a letter addressed to kristene chapa's father. >> what does the letter say? >> the letter is written from the perspective of a hitman who has been hired to kill the surviving victim in this case, kristene chapa. >> reporter: in the letter, the hitman even named the person who had hired him. if you're wondering, the letter does not mention dylan spellman.

all of it was a twist as big as texas. coming up -- the mysterious letter. could this be the smoking gun police had been looking for? >> immediately i knew this was something very big and very important. >> when "dateline" continues. fu. party's over, 'six legs', she's got simparica now. simpari-what? simparica is what kills tick and fleas, like us. kills? kills! studies show at the end of the month, it kills more ticks in less time than frontline plus and nexgard. guess we should mosey on. see ya never, roxy! use simparica with caution in dogs with a history of seizures or neurologic disorders. the most common side effects are vomiting, diarrhea, and lethargy. say goodbye to ticks and fleas... with monthly simparica chewables. ...the only eye drop... ...approved for the signs... ...and symptoms of dry eye. because dry eye can mean... ...more than... ...just dryness. xiidra may provide lasting relief... ...starting in two weeks. one drop in each eye, twice a day.

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you'll ask... what pain? with advil ♪ protect your pet with the #1 name in flea and tick protection. frontline plus. trusted by vets for nearly 20 years. >> reporter: while detective aaron veuleman continued trying

to strengthen his case against dylan spellman, investigators in neighboring sinton, texas, received a mysterious letter addressed to kristene chapa's dad. >> immediately i knew this was something very, very big and very important. >> reporter: the letter writer described himself as a hitman hired by the person who'd shot mollie and kristene. he wrote the gunman had sought his services to finish the job and make the only witness to mollie's murder disappear. >> what he's saying is, "i was hired to kill kristene, but i'm not gonna do it. instead, i'm warning you." >> that's right. >> he's telling kristene chapa's father, "i'm gonna tell you who the murderer is, and then you can go do something about it." >> reporter: the letter contained details police had never mentioned in public. >> that he forced the girls to duct tape themselves. the fact that he called them by numbers, "girl number one,"

"girl number two." >> reporter: then, the biggest revelation of all. >> who does he say the murderer is? >> he identifies him. his name is christobal melchor, and he gives an address in utah. >> reporter: christobal melchor from layton, utah, to be precise, just outside salt lake city. melchor worked in the area as an army reservist. >> had the name christobal melchor crossed your desk in any way during this investigation? >> in the two years prior to this investigation, we had never heard that name. >> reporter: the hitman even included a photograph of mr. melchor, the man he said hired him. >> this guy's being handed to you on a plate. >> yeah. >> reporter: could it be real? should police take this at face value? >> is it possible that this letter is some sort of thinly veiled threat to kristene, you know, "you've survived, but we know where you live"? >> yes. the letter definitely contained an implied threat to her safety. and so we moved very quickly to make sure that she was safe, that she was protected. >> they're like, "okay. you know what?

you need to leave town." no one could no where i was at. only my family knew where i was at. >> reporter: with kristene in a safe place, veuleman went straight to layton, utah. with the help of the local pd, he was soon sitting across from his new person of interest. >> christobal melchor said that he was on a training exercise in fort hunter liggett, california, at the time of the murder. >> not only was he not in texas, he was on the other side of the country. >> he was. >> was there anything to suggest that he had some kind of vendetta against the chapa family? >> we were not able to find any connection between christobal melchor and the chapa family or the olgin family. >> reporter: veuleman then showed melchor the letter, and melchor was stunned. >> but he was even more surprised when he saw his picture on the last page of the letter. >> reporter: that was because melchor immediately recognized the photo. he knew when and where it was taken. plus, he said, the original

photograph was of two people. the missing man, he said, was his former roommate, david strickland. if the snapshot was a surprise to melchor, the name david strickland was an even bigger one for detective veuleman. turns out, he'd crossed paths with david strickland before. >> i'd interviewed david strickland in 2012 just days after the murder. >> reporter: remember that tip about a white car seen speeding from the park the night of the murder? the tipster was david strickland. >> he came in as a good samaritan, wanting to provide information. >> reporter: back then, david strickland lived just blocks from the park where the shootings took place. >> and now here he is being mentioned in connection with a guy who's been mysteriously fingered for the murder. >> that's right. >> so just like that, basically, mr. melchor is no longer the focus of this. it's now david strickland. >> that's right. >> reporter: chris melchor went

on to explain that he and strickland were no longer on good terms. melchor believed strickland had stolen several of his guns, so he had strickland arrested. >> the gun robbery put a damper on their relationship. >> reporter: strickland pleaded not guilty to the gun theft charge and was released soon after, but the charges were still pending. and veuleman wondered, "could strickland have written that letter as some kind of elaborate payback for melchor having strickland arrested?" >> i know there was bad blood between david strickland and christobal melchor, but to accuse someone of murder? >> if you think that letter was written by david strickland, and you think the letter includes things that only the killer would know -- >> well, i think the logical inference was that strickland had something to do with the murder. >> reporter: finding david strickland was now vueleman's priority. according to melchor, strickland left utah after his arrest and returned to texas, so detective veulemen did the same, hoping

this man would turn out to be the investigation's third, and final, person of interest. coming up, a suspect, not acting at all like you might expect. >> he was enjoying this interview. >> maybe police have the wrong guy again. >> want to point at him in court and say that's the guy that did it. >> when "dateline" continues. protect your pet with the #1 name in flea and tick protection. frontline plus. trusted by vets for nearly 20 years. i'm and i'm an emt.erer when i get a migraine at work, it's debilitating. if i call out with a migraine, that's one less ambulance to serve a community. i just don't want to let these people down. excedrin migraine. relief that works as hard as you do. whthe moment you realize you didn't really mean "any color you want." we want you to feel great about your color choice. that's why we have a paint guarantee.

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welcome back. a mysterious letter had identified cristobal melchor as the man who shot kristene chapa and her girlfriend, mollie olgin. after police spoke with melchor, they turned their attention to his former roommate, david strickland. police wanted to hear what he had to say, and they were not the only ones. here's josh mankiewicz with the conclusion of "a texas twist." >> first came dylan spellman, cleared by police and by his height. then kris melchchris melchor, ad of suspicion by geography. now the detective us with on the trail of another man, david strickland. the detective learned that strickland was a hometown boy, his dad, a successful business man. strickland served briefly in the military and was now newly married. then vollomman saw photographs

of david strickland's possessions, which had been seized at the time of his arrest on the gun theft charge. >> i'll never forget the first photograph that popped up. it was a glock .45 caliber pistol and an under armour glove and you could see very clearly the white under armour logo. >> a glock .45, the type of gun the crime lab was suspected to shoot the girls. as for the black glove, kristene was absolutely certain that the shooter wore a pair exactly like that. >> i know that, because i played softball and that stuck out to me right away. >> detective vollomman immediately sent strickland's gun to be tested, to see if it fired those two spent shell casings at the crime scene. he didn't have to wait long for the results. >> what that report said was that the two shell casings found at the scene and the two shell casings from the test fire were

linked to the same weapon. >> for detective volloman, that report was nithe missing piece the puzzle, which he believed now directly linked david strickland to the shooting. >> the day i looked at that ballistics report is the day we arrested david strickland. >> the charges, aggravated assault, aggravated sexual assault, and capital murder. while in custody, david strickland agreed to sit down for a police interview. >> just have a seat for me. >> county prosecutor sam smith watched the interview through a one-way mirror. >> at some point you saw mollie and kristene? >> he would claim to have committed the murder. >> you're saying that you did this. >> sure, i did it. didn't everything say i did? >> and then in the next sentence, with a smile on his face, say, that's what you wanted me to say, isn't it? >> whatever you want to hear,

boss. >> so it was like a game? >> very much a game. he was enjoying this interview. >> four years after kristene chapa was raped and shot, four years after mollie olgin was murdered right next to her, david strickland face adjued d f 12. >> were you worried? >> of course i was worried. i didn't know how it was going to turn out. >> when you saw mr. strickland for the first time, what'd you think? >> i didn't know what to think, to be honest. just thinking, he did this? >> he wasn't the monster you imagined? >> no, he wasn't. sometimes those are the scariest people, though. >> prosecutor smith laid out his evidence, from gunshot to snapshot to mug shot. the gun, the shell casings, and the gloves. as for the letter, smith told the jury police had found remnants of it on david strickland's computer. >> you can delete the letter off of your computer, but if you've

used the spell-check/grammar check function, that information is still stored in the community. >> and that's what you found? >> and that's what we found. >> why do you think mr. strickland wrote that letter? he had to know that suspicion would eventually boomerang right back on him. >> that's what most people would think. >> it's a foolish thing to do. >> it's a very foolish thing to do. >> before prosecutor smith rested, he called kristene to the stand, putting her face to face with david strickland. >> i want him to see me and see what he had done, but he would not look at me. >> defense attorneys john gillmore and jimmy grandberry don't dispute that kristene was a sympathetic witness, but in court they argued she was also unreliable. >> she didn't know who shot her. she has no recollection. she wasn't able to pick our client out of a photo lineup. >> she wasn't able to point at

him in court and say, that's the guy that did it. >> what's more, kristene initially told police that the shooter's gun was silver. >> david's gun is a glock, which is black. >> they also went after investigators, saying they'd bungled the lengthy two-year investigation, saying evidence was mishandled. >> we had evidence that evidence was mishandled from the chief of police, chastising the officer who mishandled the evidence. >> he admits mistakes were made. he's now retired. the second lead detective was let go for sharing sensitive details of the case with someone outside the department. strickland's attorneys concede their client may have written that letter, but they argue it would only have been out of revenge for chris melchor having him arrested. as for those confidential details in the letter? >> this is a small town, texas. there's any number of places

that this kind of information could have come from. >> but what about the lab report showing strickland's gun matching the shell casings found at the scene? >> we had our expert, who said that it's inconclusive. there's no way you could say for sure. >> police, they said, should never have taken their sights off the real shooter. >> well, they had the right guy. >> dylan spellman? you think that's the killer? >> he's a better match than my boy. >> he had just failed a polygraph exam and then started trying to plea bargain. >> this is a guy that kicked in a door with a group of people, wearing masks, went in, and held a family hostage, terrorized a family. it takes a special kind of mind that wants to do something lake th -- like that. >> and strickland's attorneys point out that his client had no history of violence at all. >> david strickland did not do this. >> it was sam smith who had the last word. dylan spellman, he told the jury, might have been under suspicion, but ultimately had

nothing to do with this crime. david strickland, he said, was the man holding the gun. >> shooting both of these girls for no identifiable reason at all, he's certainly a psychopath. >> prosecutor smith never offered the jury a possible motive. kristene says, she's sure it was about her sexual orientation. >> what's the reason for thinking it's a hate crime? >> in the letter that he supposedly tried to send to my dad, said something in the letter like, those [ bleep ]less be -- lesbians. >> reporter: in his interrogation, strickland made a point of saying he had no issue with the gay community. whether or not that was the truth, prosecutors chose not to charge him with a hate crime. after five days of testimony, the jury began deliberations. it took six hours to reach a verdict. guilty. david strickland is appealing

that conviction, based on the fact, his lawyer says, the evidence presented was legally insufficient to convict him. strickland was sentenced to life in prison. for mollie's family and friends, that guilty verdict, as it often does, provided hollow satisfaction. >> we were waiting for justice and now it's here, but we don't get her back. >> we have had so many huge, major life moments and she hasn't been there. >> what would have been our anniversary, her birthday, the anniversary of us getting shot, those days are the hardest. >> kristene still wonders how she escaped death and sometimes, why. >> i do have survivor's guilt. i mean, hopefully it will go away in time. >> kristene would tell me, why was it me? why didn't she survive? and i told her, there's a reason

she was still living and to be happy and live on for mollie, because mollie didn't get that chance. >> that's all for this edition of "dateline." i'm craig melvin. thank you for watching. good morning. i'm dara brown in new york at msnbc world headquarters. it is 7:00 in the east, 4:00 out west, and here's what's happening. new concerns about north korea increasing nuclear production at secret sites. what nbc news has learned about kim jong-un's efforts to keep his program alive. a call for change at a nationwide protest, but will demanding the abolishment of i.c.e. backfire on democrats? and the change coming to the supreme court and what it means for abortion. how chief justice john roberts could play a key role in an unexpected way. new t