thomas or roger or mary. i'm craig melvin. >> and i'm natalie morales. >> and this is "dateline." >> she was crying and crying. i said what's wrong? and she says debbie's dead. we all wanted to believe that it was an accident. there's no possible way he could do this on purpose. >> reporter: a dark house. a husband with a gun. a wife, dead, on the floor. >> make sure that she is still breathing. >> i don't think she is, damn it. >> there was no question who killed her. the mystery was, why? >> i hear the door squeaking and

i hear the grumbling, and i hear the dog growling. >> how could you not tell that's your wife? >> it was dark. >> he just kept saying it was an accident. he said he didn't do anything wrong. >> reporter: others disagreed. >> we never, for a second, believed that he didn't know who that was standing in front of him. >> was it a tragic mistake? >> he was broken. >> reporter: or cold-blooded murder? >> these bits of emotion are only done in front of the detective. they're not done when he's alone. >> a room too dark to see? >> so let's shut the light off. >> reporter: or a story too hard to believe? >> there was nothing accidental about what he did. >> reporter: a shot in the dark and doubt in the light of day. >> the love of your life? >> yes, sir. >> the person you know better than anybody else. >> yes, sir. >> and you can't tell it's her when you pull that trigger? >> welcome to "dateline." theirs was a marriage of

opposites. she, the hard-charging businesswoman, he, the easygoing contractor. and yet, somehow, debbie kelly and lars ipso made it work. or, so it seemed. until a gunshot ripped through the night, leaving debbie dead and a family racked with doubt. was her death the case of mistaken identity? or the bloody end to a marriage gone bad? here is andrea canning with "the silhouette." >> reporter: what happened inside this house would destroy everything the woman who lived there had worked for. she finally had it all. the career, the dream home, the marriage she'd waited so long for. >> there was a brightness in her eye. >> i trusted that she knew her heart. >> they were in love. there's no other way around it. >> reporter: her life, now complete. fulfilled. safe.

>> we never worried about her. >> reporter: but was it all an illusion? >> send an ambulance, please. >> reporter: what happened that morning, in the predawn hours in the dark? >> right in the friggin' chest. >> reporter: the women at this san anton san antonio racket club say you can tell a lot about a person by the way they play tennis. >> i think tennis, in general, just really brings out your personality. >> brings out either the best or the worst in you. >> as for who had the best character at their club? the answer comes as fast as a serena williams serve, their friend, debbie kelly. >> debbie, for me, was kind of the whole package of a person. fair. fun. and a great leader. >> reporter: debbie. fiercely independent, driven. >> always, wanted to be a career woman. >> reporter: she climbed the corporate ladder in healthcare.

her mom and dad, jim and anne kelly, marvelled at her commitment. >> she spent many, many hours traveling and many hours working overtime. >> reporter: but debbie hadn't found as much success in her personal life. she got married, in her 20s, but it didn't work out. now, in her 40s and dedicated to her career, there was little time to look for the right guy. >> is it hard to date? >> it was hard for her to date. >> reporter: so in 2008, debbie took a new job that allowed her to focus a little more on her personal life. that's when she got serious about her tennis game. >> she was a little bit of a tiger. >> reporter: that's how she met this bunch. betty pace, serette kelly, and ellen mitchell. >> she was not a big person. but all of her went up and the hair would fly up. and she would smash that ball. >> the ladies clicked off the court, too. bonding over post-match drinks. >> she had a great laugh. she throws her head back and chuckles and just her whole body laughs.

she had a real silly, funny, quirky side. >> so, i've heard that she was very private. would she talk about dating? and guys with you all? >> not with me. uh-uh. >> she just wasn't one to talk about herself, period. but i was always trying to find her somebody. >> how did she receive betty the matchmaker? >> well, she would always be like, oh, no. >> reporter: husband or not, debbie was ready to plant some permanent roots. she bought a house, in a gated community, and began to remodel it on her own. she told her friend, liz savia, all about it. >> was she like an hgtv-type of girl? >> yes. oh, my gosh. hey, i'm going to home depot. she's working on the sprinkler system. or she's deciding on materials for the floor. >> reporter: but the busy executive couldn't do everything herself. so, in 2012, she hired a contractor. his name was lars itso. but once work got underway, lars

seemed in no rush to finish the job. >> she was getting very frustrated. and she's like, i wish this person would finish. >> but lars's siblings, ken and christy, said he wasn't dragging things out for the money. he had an ulterior motive. >> he goes yeah, she keeps flirting and talking and we're laughing and having a good time. >> lars liked debbie, and he thought it was mutual. >> and he goes, can i ask her out? yeah, i said why can't you? >> reporter: so, began an unlikely courtship between debbie, the petite powerhouse, and lars, the 6'2" nordic he-man. debbie got a kick out of lars' laid-back ways. just a guy into old-school board games, restoring muscle cars, and drinking texas's favorite homegrown soft drink, dr. pepper. >> a case a day. >> at least a 12-pack. >> i've never heard of someone

drinking that much dr. pepper. >> i thought it would kill him. doesn't drink a lot of alcohol, at all. just dr. pepper. >> and when private debbie brought lars out to meet her friends, they knew it was serious. >> and he arrived with her, hand in hand. >> sure, they noticed lars was a different match for their friend. >> he's very quiet. >> he's got the blonde hair that would go with being named lars. >> he seemed like a surfer, big man. >> but, to debbie, he was the right man. >> i felt like she was really in love with him. >> i can understand her thinking, you know, maybe, it's time to try something just different. >> reporter: and pretty soon, that something different was official. after a year of dating, debbie and lars were engaged. >> so baby brother finally settled down. >> he did. and he was happy. never seen him that happy. >> they married, soon after, at

this chapel in arkansas, near her parents' homes. >> how beautiful did she look on her wedding day? >> the main thing is she just looked so happy. that was really important to me. >> reporter: debbie and lars embrace the contented rhythms of married life. spending weekends with family. enjoying the outdoors, and her dog, cody. but after two years together, things started to change. debbie got a coveted promotion to vice president. >> that was going to entail more traveling and a lot more working, too. >> reporter: big responsibilities, more pay, but less time at home. less time with lars. october 9th, 2015. debbie, recently back from a business trip, went to bed early for a morning tennis game. debbie's beloved cody slept on the floor, beside her. the shades were down. lars joined them, a little past midnight. four hours past. and then --

>> san antonio 911. >> uh, just had a gun shot. >> what had happened in that texas home? coming up. >> i thought there was a burglar in the house. >> danger in the night. and a confrontation in the dark. >> oh, baby. >> when "dateline" continues. cs [♪] did you know you can shorten your cold with cold-eeze® lozenges. cold-eeze® can shorten your cold by 42%.

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called 911. >> i'm a male. she's a female. will you send an ambulance, please? >> that female was debbie, shot and gravely wounded. >> i want you to walk over to her, and make sure that she is still breathing. >> oh, i don't think she is, dammit. >> reporter: the 911 operator guided lars through cpr. >> kneel beside her. stack your hands. >> [ bleep ]. oh, baby. oh, man. right in the friggin' chest. oh! >> reporter: police raced up to the house, dash cams rolling. the audio kept recording as they entered the house.

they found lars, standing over debbie's body, back by the bedroom. >> go ahead, and back up, please. >> as an officer tended to debbie, lars tried to explain how the shooting happened. >> i thought there was a burglar in the house. thought there were multiple people in the house. >> what did you hear? >> i heard voices when i was in bed. >> and where did you hear the voices at? >> out front. >> front? after you heard the voices, what happened? >> i got up, my wife was in bed with me. i grabbed my shotgun. >> reporter: as emts took over trying to save debbie, lars went with police down to the station. they, urgently, needed more details. where were the intruders? were they harmed? what did lars know? what, exactly, did he do? sitting in the interview room, wrapped in cody's dog blanket, lars took them through what happened, step by step. he said he was awakened, around

4:00 a.m., by strange noises in the house. >> i hear the front door or the door squeaking, and i hear a grumbling. and i hear the dog growling. >> reporter: he said he'd never heard cody growl before, so he was instantly on alert. >> did you think they were male voices or female voices? >> i thought they were male. >> lars says he moved toward the sound that he heard, with his shotgun in hand. he reached this tiny hallway, where he says he saw a silhouette standing in front of him, about three feet away. he says he made the split-second decision to fire his gun, fearing for his life. all of this happening, he says, in the pitch-black darkness. >> about how far away were you? >> me to you. >> okay. >> reporter: but the person lars shot was not an intruder. it was debbie. police quickly determined that the only shot fired in the house came from lars's gun. he said it was an accident. a case of mistaken identity.

>> everything happened so fast. >> reporter: nevertheless. >> any kind of infidelities going on or anything like that? >> no, sir. i trust her complicitly, completely. >> lars answered each of the investigators' questions. in turn, he just wanted to know one thing. >> nobody's told me anything about if she is all right. >> reporter: so after two hours of talking, they broke the news. >> i don't know how to tell you this, but your wife didn't make it. okay? she is deceased. >> reporter: just before 10:00 a.m., police let lars go. ken and christy remember their younger brother that morning, overwhelmed with grief. >> he was completely hurt. shattered. you know?

he -- he was broken. >> in those hours afterwards, what was he talking about? >> he really wasn't talking. >> he was just in shock. >> yeah. >> if he opened his mouth, he broke down. >> reporter: across town, debbie's tennis friends were on the court, waiting for her to start their match. >> so he called me over, and said that lars had shot her. >> what are you thinking when you hear that? >> it was very surreal. >> i mean, i couldn't comprehend, how could someone shoot somebody? it -- it didn't even make any sense to me. >> in arkansas, jim and anne kelly learned the news from their son. >> that's just the worst news that a mother could ever hear. how does your brain process that information? >> i don't think you do. i couldn't process the shooting part, i guess. just that she was gone.

and part of me died the day she died. >> just kept saying, not debbie. not debbie. not deb. >> debbie's parents flew to san antonio to spend time with lars. to support him, in their shared grief. >> he could hardly talk. he seemed extremely remorseful. >> was he saying everything that you would want to hear? like, i -- i messed. i did it. i'm sorry? >> he apologized, profusely, for it. and said it was just an accident. it was dark. >> some people might be really angry. but you didn't go down that load. >> we did not go down that road. we supported him. >> reporter: but that support was about to be put to the test. >> coming up. >> i know that she was frustrated. >> how strong was that marriage? how dark was that night? >> that's your wife. height, weight, shape. how could you not tell that's your wife? >> when "dateline" continues. >> when "dateline" continues give you my world ♪

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>> reporter: lars itzo admitted he fatally shot his wife, debbie, but said it was a terrible accident. from the very beginning, he cooperated with police, answered every question, no lawyer present. then, about eight hours after that first conversation about the shooting, lars headed back to the station and sat down for a polygraph test.

>> he volunteered to go do it. like, i'll go take a polygraph. >> because he said he didn't do anything wrong. >> reporter: but the polygraph indicated lars was deceptive in some of his answers. his brother and sister said it was perfectly understandable. >> well, he's nervous. he's in shock. you know? >> he couldn't even get his name right. his birthday. where he was born. >> reporter: maybe so. but his performance on the polygraph was enough for detectives to grill him relentlessly. >> how could you not see that was a woman? >> it was dark, sir. >> reporter: no matter how dark it was, how scared he was, how could lars fail to recognize debbie, three feet away? >> that's your wife. height, weight, shape. how could you not tell that's your wife? >> it was dark. >> do you understand how lame that sounds, lars? >> it's the truth. >> you're 36 inches from a human being, and you can't tell it's your wife? i don't care if it's pitch dark.

no room is completely dark. there's going to be a light from every room. it may not be much. but it's enough to tell a shape. you obviously saw something because you fired the gun. >> lars insisted he thought there were intruders in the house, and he and debbie were in danger. >> i thought there was somebody in the house going down the hallway, the other direction. i thought there was bone coming at me, this way. >> what made you think that? because your dog growled? >> yes, sir. he never growls. he barks. >> reporter: there was no witness or apparent evidence to contradict him. after an hour of questioning, police, once again, let lars go. six days later, he said his final good-bye to debbie. her parents, by his side. >> how was lars at the funeral? >> very composed. very reserved. he stood up with me. >> what did that say?

that the family was supporting him? >> it said a lot. it was great. >> reporter: debbie's friends weren't nearly as supportive. >> did you say anything to him? did he say anything to you? >> no. >> i didn't approach him. >> i did not. >> they were furious at lars for doing something so stupid, so careless. everything he did bother them. even, his taste in flower arrangements that day. like the one that's pictured here. >> there was a wreath up at the front, that was a huge, flower heart. and in the middle of it, it was broken with these lines. so it was this broken heart. and it actually looked like a heartbeat and it was in such poor taste. >> she was actually shot in the heart? >> well, it penetrated the lining of her heart, yes. >> reporter: as family and friends tried to sort out their feelings, police reviewed the case. looking to see if this was a crime, or not. since, even an accident can warrant criminal charges. and, sure enough, 11 days after

lars fatally shot debbie, he was charged with manslaughter. prosecutors, carl alexander and leo gonzales, caught the case. >> why did manslaughter fit? >> manslaughter is defined, in the texas penal code, as causing the death, recklessly. it was, somehow, somewhat of an accident. >> lars was released on bail. >> debbie's parents continued to support him. >> manslaughter's still, in our understanding, would be an accident. okay? and so, we go forward from there. >> reporter: but as the days without debbie stretched into weeks, something cooled in their relationship. >> he starts changing and turning my connections with him. and he -- not so forthcoming. if i ask him something, he kind of holds back. >> lars's sister said his behavior could be explained. he had sunk into a deep depression. >> he just kept saying he wanted

debbie back. if he could get her back, it was an accident. he was sorry. >> reporter: investigators, as they worked through the case, looked into the couple's finances. debbie's assets totaled more than a million dollars, when she died. her dad was named the beneficiary on most of her investment accounts. so lars, it seemed, had little to gain by killing her. still, the whispers continued among debbie's friends, who told investigators there was another side to the marriage. >> i know that she was frustrated. >> reporter: even simple things caused tension. liz savia volunteered that lars, the contractor, was slow to finish projects around the house. >> she did send me a picture of what lars did in the bathroom. and the measurements were incorrect. and so, it ended up making a hole. she goes, i just want my bathroom fixed. >> she would express frustrations about lars sitting around on the couch, all day,

and watching tv. >> reporter: debbie's friend, ellen mitchell, noticed a change in debbie's behavior when she returned home from business trips. >> she would come home from some of these trips. and say, hey, let's go, you know, get a drink. let's have some dinner. and your expectation would be i want to get home to my husband. she didn't seem to be in any particular hurry, anymore. >> looking back, now, debbie's parents wonder if the marriage frayed because debbie, the modern woman, wasn't meeting lars's old-fashion expectations. >> she was not the kind to stay home and bake cookies. or walk in the door and serve you a meal because she'd work just as hard, too. >> and all these friends. she goes and spends tennis time, does things. >> he wanted more of debbie? >> he did want more of debbie. >> all marriages have problems. very few and this badly.

so investigators decided to take an even closer look at the husband who pulled the trigger. >> coming up. lars seemed upset. was he? >> these bits of emotion are only done in front of the detective. they're not done when he's alone. >> when da"dateline" continues. alone. >> when da"dateline" continues o. building an experience that lets you shop over 17,000 cars from home. creating a coast to coast network to deliver your car as soon as tomorrow. recruiting an army of customer advocates to make your experience incredible. and putting you in control of the whole thing with powerful technology. that's why we've become the nation's fastest growing retailer. because our customers love it. see for yourself, at carvana.com. itchy? scratchy? family not get charmin ultra strong. it just cleans better, so your family can use less. hello clean bottom!

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hello, i'm dara brown. here's what's happening. 49 million people are under exce excessive heat warnings across the west. to cool off from the blistering heat, l.a. county officials are expecting tens of thousands to flock to the beaches. they are, however, urging people to wear masks and stay away from people they don't live with in an effort to curb the spread of the virus. now, back to "dateline." of the virus. now, back to "dateline."

as 2015 gave way to 2016, investigators weren't so sure debbie kelly had been happy in her marriage to lars itzo. and they took a closer look at the circumstances of her death. they pulled all those recordings from the day of the shooting. examined lars's behavior. his turns of phrase. even, things he didn't do. starting with the 911 call. this is lars, in the first moments of that call. >> gun shot. i thought somebody was in the house. my wife. >> you shot somebody? >> yes, ma'am. >> what's your name? >> my name is lars itzo. oh, man. >> what do you make of this tone from lars? >> he's not really that upset about what he's done. >> i thought he was having more of an aw, shucks moment. >> but, within moments, lars

became frantic. hyperventilating. moaning. the question. was it for real? >> the way he switched up emotions from when he starts doing cpr, it sounded a lot like mouth breathing. >> to me, it soundacting. >> on the 911 call, he set the scene this way. >> i don't know what it was. i just seen light and i heard movement. i thought she was right next to me when i got up out of bed. >> reporter: to responding officers, he changed the order of events. telling him he saw that light, after he got out of bed. >> i got to the doorment i see a flav of light coming from the front of the house. >> and lars added various, new details to his story. >> i heard the dog growling.

>> reporter: in his interview down at the station, lars revised his story, again. that's when he said he woke to the front door squeaking. and offered, for the first time, this description of how he realized he'd shot debbie. >> and i hear this groaning and i knew it was my wife. >> reporter: during those interviews, lars appeared heartbroken. at times, falling apart. >> he was described as pacing in the blanket. he was mumbling. moaning. >> at various times, yes. >> yes. >> is that not the -- what a husband should do after something like that? it sounds normal. >> well, that's the thing. it sounds normal, right? but when the detective looks at him and he doesn't see any tears. okay, that doesn't jive with everything else. >> these bits of emotion are only done in front of the detective. they're not done when he's alone. >> what was he doing when officers were not watching him? >> sat in this manner, sleeping at moments. >> and sipping his signature

drink, dr. pepper. free on bail, lars understood he was still under the microscope. >> it was difficult. he didn't sleep much. >> watching lars suffer was torture for ken and christy. they knew how much their brother loved debbie and how dark and confusing that house could be at night. >> you felt it was important that we come to the house, now. >> yes, i did. >> why? >> because no one realizes how dark it was. >> we're here. it's around 4:00 in the morning. >> yes, it is. >> reporter: this was lars and debbie's bedroom. ken itzo walked us through the story lars told him countless times. >> he wasn't sure what he was seeing. he just thought it was an intruder, maybe two. >> there's the thought, well, debbie's only 5'3". she's bond. she was wearing a light t-shirt. how could he not see his wife? >> at 4:00 in the morning, you don't see anything. i don't think size, weight, or complexion matters, at 4:00 in the morning.

when you're awakened by a noise and your dog's growling. >> reporter: ken wanted us to experience it with the lights off. >> let's do it. >> so let's shut the light off. >> reporter: at first, it was pitch black. but as my eyes adjusted, i could make out something. >> i can see a little bit of a silhouette. but i cannot see your face. i'm going to turn the light back on. i believe i was standing about where lars was standing. you were standing about where debbie was standing. i will say, he would be able to see, probably, about the height of the person. >> right. >> if he has similar eyes to me. >> and that depiction means absolutely nothing, at 4:00 in the morning. >> what's your reaction to that? does that change anything? >> by her size, alone, he should've known it was her. a silhouette. i mean, three feet away. he should have known that that was his wife. >> reporter: prosecutors believed it simply was not as dark that morning as lars claimed. and said photos from inside the house proved it. >> this is the big picture

windows. they're there in the living room. the drapes are never pulled back. >> where the shooting happened? >> it would've been over here. >> these are the windows the prosecution made such a big deal about. even the curtains are exactly the way they were the morning of the incident. they believed ambient light would have had to have seeped through these windows, from neighborhood streets, from homes, even the night sky. >> prosecutors believed that ambient light was never for lars to see debbie's silhouette. they factored in, his inconsistent behavior, his shifting story. >> when you kind of put it all together, there was nothing accidental about what he did. >> reporter: five months after debbie's death, the state made its move. >> had you all kind of thought maybe this was going to go away, since so much time had passed? >> i was kind of hoping it would. >> reporter: instead, on march 3rd, 2016, lars itzo was rearrested. the charge this time? murder. >> coming up.

a very thirsty suspect. >> i enjoy dr. pepper now and again but i don't want to drink a dr. pepper when my hands are covered in my wife's blood. >> but does that make lars a murderer? when "dateline" continues. makea murderer when "dateline" continues. eliminate odor instead of just masking it. and is made with three times more odor fighters. with secret, odor is one less thing to worry about. secret. an extra 15% credit on car and motorcycle policies? >>wow...ok! that's 15% on top of what geico could already save you. so what are you waiting for? idina menzel to sing your own theme song? ♪ tara, tara, look at her go with a fresh cup of joe. ♪ gettin' down to work early! ♪ following her dreams into taxidermy! oh, it's...tax attorney. ♪ i read that wrong, oh yeeaaaah! geico. save an extra 15 percent when you switch by october 7th. ♪ give it up for tara!

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did you know you can shorten your coldrd and we're [♪]e for you. with cold-eeze® lozenges. cold-eeze® can shorten your cold by 42%. it releases zinc ions that some scientists believe inhibit cold viruses from replicating. try cold-eeze® the number one best-selling zinc lozenge. >> reporter: was lars itzo a loving husband, who made a

deadly mistake? or a killer trying to cover his tracks? that was the central question, as the people versus lars itzo. the stakes were high. if lars was convicted of murder, he could face up to 99 years in prison. if he was convicted of manslaughter, as few as two. >> we never, for a second, believed that he didn't know who that was, standing in front-of him. >> but the prosecutors knew, proving intentional murder wouldn't be easy. >> especially in this case, though, where you have someone saying i did it, i confess. but it was an accident. i love my wife. >> yeah, we were aware of that. and we were willing to accept that challenge. >> lars's attorneys believed their client, and thought the jury would, too. >> this was simply a terrible accident. >> when i first met lars, i could see his remorse. and after speaking with him, i said this man didn't do anything

on purpose. >> reporter: the prosecution started off in dramatic fashion. they played lars's 911 call for the jury. as the tape rolled, lars shook and sobbed with his entire body. once again, the prosecution wondered, was it real remorse? >> i have small children. i have seen that face before. and it usually involves just before a dirty diaper. >> now, that's a first on "dateline." >> he had that expression of bearing down and he was kind of turning red. and you never saw a tear. >> reporter: next up, the first officer on the scene that night. he testified that lars didn't look like a man, who'd been doing cpr on his mortally wounded wife. >> he was clean. >> what do you mean by clean? >> he didn't -- he didn't have any blood on his body. once i saw him doing some cpr, then he had blood on his hands. >> detectives told the jury lars put on an emotional display. >> sobbing noises. you know, just --

>> ever see a tear? >> no. >> reporter: they played that video of lars at the police station, to show how he seemed to keep adding details to his story of the shooting. and how, in the midst of tragedy, lars still had the presence of mind to ask for his favorite beverage. >> here you go, mr. itzo. >> i enjoy dr. pepper, every now and again. but i don't want to drink a dr. pepper when my hands are covered in my wife's blood. he doesn't even seem to take notice of that. there was one point, in the video, where he actually sees it. and kind of wipes it off on the blanket. no big deal. >> little debbie. it's cool. >> reporter: the prosecution's case revolved around this question. around 4:00 a.m., in a dark house, could lars see well enough to know who he was shooting? liz savia, a frequent house guest of debbie and lars's, testified she could

easily see at night in their home. >> there was enough light coming through the big windows that i could find my way. >> reporter: and remember, debbie was only about three feet away when lars shot her. prosecutor carl alexander wanted to show the jury just how close that is. >> what was the experience? >> terrifying. >> why? >> i'm a gun owner. one of the absolute cardinal rules of -- of using a firearm is you do not point the barrel at anything you do not intend to destroy, ever. i knew it was unloaded. but in that moment, my pulse skyrocketed. >> he wanted the jury to think hard. no matter how dark it was, wouldn't you recognize your own spouse? >> he knows her scent. he knows her sound. he knows her shape. and he knew who that was in front of him. >> after laying out how lars killed debbie, the prosecution thought the jury would want to know why? what was the motive? the couple, they said, had hit a breaking point.

liz savia testified that her hard-charging, multi-tasking friend, debbie, found lars a little too laid back. >> like, there was always a project and it was taking a long time. >> who was? >> lars. >> so she was frustrated with lars. >> yes, sir. >> reporter: the prosecutors told the jury this marriage of opposites became too lopsided for lars to handle. >> she took time. work was very important. she took time out to go have dinner with friends and family. he wasn't a factor. >> basically, she didn't consider him enough to be a part of her normal, everyday life. >> reporter: they said lars wanted more from debbie. and when he didn't get it, he got rid of her, instead. >> this is a new one for me. one of the possible motives that was brought up. that lars was old school and was upset that debbie did not take

his last name. >> she was a professional woman and she was very driven. and i think that's part of why she didn't take his name. she kept everything separate. >> including her bank accounts. she never put lars's name on them. >> this was not about money. >> no, it -- it wasn't. i think it really has to do with he loved her more than she loved him. >> reporter: when its turn came, the defense said, of course, lars loved debbie, which is exactly why he did not murder her. >> lars itzo accidentally shot and killed the love of his life. what he is guilty of is making the most horrific mistake of his entire life. >> and they called a reluctant, surprise witness. debbie's own mother, whose early support for lars had waned. she did not want to testify on his behalf. >> i didn't take it well. i actually started screaming at the attorney.

>> reporter: but anne took the stand. lars's attorney showed her a check she once wrote to debbie. >> who is the check made out to? >> debbie itzo. >> reporter: debbie itzo. proof, the defense argued, that independent debbie, sometimes, went by her married name. they called lars's friends to say the couple's marriage was solid. >> how would you describe his relationship with debbie? >> perfect. it was very good. >> you ever notice any -- >> no. >> christy itzo explained how her normally stoic brother was overcome with profound grief. >> he was crying. he was curled up in a ball. he grabbed me. we cried for like 20 minutes. and all he wanted was debbie back. >> reporter: but the defense knew their case hinged on one thing. lars's state of mind, the moment he pulled the trigger.

and there was only one person who could tell that to the jury. >> coming up. a grieving husband? or a lying one? >> the love of your life. >> yes. >> person you know better than anybody else? >> yes, sir. >> and you can't tell it's her when you pull that trigger? >> when "dateline" continues. tr >> when "dateline" continues fights pain in two ways. advil targets pain at the source... ...while acetaminophen blocks pain signals. the future of pain relief is here. new advil dual action.

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welcome back to "dateline." on trial for the murder of his wife, lars itzo was about to take the witness stand. what could he say to make jurors believe he simply didn't know that threatening shadow was debbie? here's andrea canning with the conclusion of "the silhouette." >> i heard a moaning. and, at that time, i knew it was my wife. >> reporter: lars itzo up on the stand, in his own murder trial, to tell the story of what he described as the perfect relationship. >> it was bliss. the best thing that ever happened to me. >> reporter: then, what everyone in the courtroom was waiting for. details about the morning debbie was killed. >> i heard a grumbling and, as i woke up, i got up to see what that was. it was pitch dark. >> reporter: lars stuck to his story that he couldn't see what he was shooting at. he thought their lives were in

danger. >> i had seen the movement in front of me, and i had pulled the trigger, at that time. >> reporter: he said he was a good man, who made a horrible mistake. >> did you, in any way, intend to cause debbie any kind of harm? >> no, she was the love of my life. >> a mistake, he said, he would regret forever. >> it still hurts? >> every second of the day. she was sent to me from god. if i could've made a list, she would've checked every box. >> reporter: on cross-examination, prosecutor alexander kmal ledged lars's key claim. that in the dark, he simply couldn't distinguish debbie from an intruder. >> you know debbie's shape. >> i know her shape, yes, sir. >> she's the love of your life. >> yes, sir. >> the person you know better than anybody else? >> yes, sir. >> and you can't tell it's her when you pull that trigger? >> no, sir. >> lars testified for two and a half hours.

but would it be enough to convince the jury he was innocent? they now faced a decision between murder, manslaughter, or not guilty. after more than six hours, a verdict. on count one, the murder charge -- >> we, the jury, find the defendant, lars itzo, not guilty. >> reporter: but before anyone in the courtroom had time to react, another verdict. >> guilty of manslaughter. >> reporter: the verdict pleased almoo e. >> no, this can't be. >> reporter: for so many on debbie's side, it was as if the jury just let lars off. >> disbelief. anger. beyond words. >> reporter: but lars's family believed prosecutors had it all wrong. >> it was about them winning. it had nothing to do with justice or the truth. >> reporter: then, came sentencing. in texas, the jury decide. it, soon, became clear they wanted to hold lars accountable.

>> for a term of 15 years. >> reporter: 15 years. just a few years shy of the maximum sentence. i spoke with lars at the state penitentiary in beeville, texas, where he says he carries a photo of debbie in the pocket of his prison uniform. >> i kiss her picture, every morning, every night. >> reporter: i asked him to describe, once again, what happened the morning he shot debbie. >> i was wake -- awoken in the middle of the night. >> reporter: the story sounded familiar, at first. but then. >> and i seen the door closing very, very, very slowly. >> reporter: he'd seen the door closing slowly? as he had before, lars just added a new detail to his story. moments later, he seemed to add another. >> believing that there were, you know, people in my house reaching for me. >> reaching for you? >> well, i just seen movement. >> reporter: so i asked lars about his inconsistencies. >> why was your story changing?

>> i don't believe it was. i don't have a script in front of me that i'm reading. this is exactly what happened. step by step by step. >> but is -- isn't the truth, the truth? >> absolutely. but to have an exact answer, every single time, it's -- that's not me. i will have an answer that is the truth, that is going to be said differently, each time. >> reporter: then, we talked about the key question. what, really, did he see before he fired the gun? >> i was in the house. >> yes, ma'am. >> and it was very dark. but i could make out your brother's silhouette. would you not clue in that, that could be debbie? and, maybe, i shouldn't pull the trigger? >> i know assailants come in very various forms. i didn't recognize that it was my wife. if it was, i would've never pulled the trigger. >> did you see her silhouette?

>> no, ma'am, i seen movement and that was all i seen was like a shadow moving. the first thing was -- in my mind, was to protect. >> did you stage this death? >> absolutely not. >> did you murder debbie? >> no, ma'am. my wife was everything. she was great, in every sense of the word. >> reporter: that offers the kellys little comfort. >> the only real satisfaction would be to have your daughter come back through the door. and that's never going to happen. >> what do you want people to walk away from watching, about her and her life? >> i think debbie was an inspiration. she will always be a part of me. and still is. >> reporter: so ambitious. so hard-working. so close to realizing her dreams. debbie's tennis friends say they miss her every day. >> i think debbie is all around us, and supporting us. and we find hints of that,

constantly, in our lives. she was a wonderful present. >> and we're blessed to have known her as a friend. >> that's all for this edition of "dateline." i'm craig melvin. thank you for watching. watching of "dateline." i'm craig melvin thank you for watching i'm craig melvin. >> and i'm natalie morales. >> and this is "dateline." one woman, two men her husband, the air force captain, and the staff sergeant, her rendezvous man. >> he was a playboy himself. >> one man too many. then suddenly, there was >> it wasn't like bang, bang, bang, bang. it was bang, pause, bang, pause. >> which sounds more like what? execution? >> you could take it that way, yes. >> a cold-blooded killing. but who pulled the trigger?