for us, that's our broadcast on a friday night and for this week. if you so very much for being with us. good night from our nbc news headquarters in new york. have a good weekend. here is the person i love, he's zig. >> her husband, a decorated military officer, shot in the dark of night. >> it was an execution. >> was this some sort of hit? >> there must have been something at work. >> that's what police thought too. until they learned about the secret life of this husband and wife. >> they meet couples on the internet. >> was it a forbidden affair? >> they were meeting for sex about four times a week. >> did it lead to murder? >> she is absolutely cold

blooded. >> soon there would be questions for a mother and daughter. >> it was another shock. the mystery of the murdered major. hello and welcome to "dateline extra." this story involves a husband and wife. he was attacked in the middle of the night, police launched an investigation that would reveal eyebrow raising secrets, secrets that might hold the key to murder. here's keith morrison. >> reporter: the wind in the northern prairie howls around the grave markers. the final resting spot for a few dozen veterans, many of whom died in combat. this is where he is resting now. major david shannon who lost his

life in 2002. his mother shirley comes here to visit and his sister brenda too when she's in town. oh, how they worried that war might put him here. except war didn't. there never was a thought back then about what could happen far from combat. what did happen? all those strange things down south in north carolina. fayetteville is an old town, steeped in revolutionary and civil war history, smack in the middle of the bible belt. but now, cargo planes buzz in and out of pope air force base. and off past the confines of the city sprawls ft. brag, home base of the computer whiz the special ops major, david shannon, his house was here just a few blocks off base. the major, his wife joan and their four children.

it was july 2002, like a sauna that night, so hot and humid, and then a light rain, the cooldown began. david and joan watched a movie on tv, fell asleep, and then -- >> i don't remember hearing the first shot, something woke me up. >> and then you heard a shot? >> and i know that whatever woke me up, i know my ears were already ringing. when i turned the light on and i see he's shot, you know, it shocks you never ever forget that image. that's burned in my brain forever, no matter how much i try to -- here is the person i love, he's dying.

>> okay, calm down. >> by the time the police and the ambulance wailed up to the door, it was too late. david shannon, just 40 was dead. all it took was a look, in fact for lead detective mike murphy to see what happened in major shannon's bedroom was highly intentional. >> it was an execution. david shannon was executed. the intruder came in while he was sleeping and placed a gun to his head and shot and placed it to the chest and shot. >> and joan? the shock of it didn't help, of course, or the fact that she was sound asleep when it happened. and by the time she calmed down enough to talk to police she wasn't very helpful. >> i did not see the person who shot david. i'm not sure if i saw or had a feeling of somebody just leaving the room.

but i form it as a shadow. >> did you actually see a shadow or did you tell the police it was like a shadow. >> there was just some movement, a shadow that had left. >> she tried to follow the intruder down the hallway, she was worried about the safety of her children, so she returned back to her bedroom. that's where she made the 911 call. >> the children, joan and david's eldest daughter daisy was out of town. their two young boys, just 7 and 10 slept through it all. unaware of what happened. down the hall was shannon's 15-year-old daughter elizabeth, who told the cops she was also in bed. and spending the night with elizabeth was her best friend vera thompson, also just 15. >> both of their statements were similar, they were listening to music, watching tv and they fell asleep. >> five people in the house, and not one saw or heard any useful thing that might help determined who committed this horrible

crime or why. there weren't many clues either, at least not in plain sight. that wasn't necessarily because the killer covered his tracks. >> the home was cluttered, it was filth, clothes all over the floor. dishes in the sink, food on the counter tops. >> and the crime scene itself? what did that look like? >> it's like finding a needle in a haystack. the house was in such disarray. >> the cops picked their way carefully, through the clutter, but found no fingerprints, footprints or any useable dna. on the floor, they found two live bullets for a nine millimeter semiautomatic hand gun. joan confirmed the major kept guns in the house. but couldn't say where those two live rounds came from. she also tried to help police make sense of the shadow images.

>> i know i wasn't 100% wide awake and aware of what was going on. there's a lot of blank spots in my memory. >> so little to go on. except there was one curious discovery in that bedroom. something unusual in a family home like this, the question was, what did it mean? coming up, solving a murder means finding a motive. >> there must have been something with what he was doing at work. this must have been a hit. >> professional or personal. the person who shot david shannon might be familiar with joan shannon. >> when the mystery of the murdered major continues.

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police began looking into the mysterious death of army

major david shannon. here again is keith morrison. dawn at fayetteville north carolina, it had been a long night at the home of major david shannon now deceased. the investigation was just beginning. the only thing that was perfectly clear was that somebody wanted this man dead. wanted it badly. shot him in the head and chest while he slept. his wife joan sleeping soundly and startled awake beside him. >> she sees a shadow of a person. >> reporter: just like that, in a split second the kids lost a father, and their life together over their 11-year marriage was over. >> david and i had a good marriage. if he were alive, he would say we had a good marriage. i do miss him, i miss what we had. there's not anybody that will ever be able to replace him. >> reporter: the murder of an army major was big news. truth be told, murders happen.

fayetteville gets its share. david shannon would be missed all right, but not just here. oh, no. murder is strictly a local event, news of this one skipped up country and across the windy prairie to a place called langdon, north dakota. that's where the major was from. this is where he grew up, where he became an unusual young man. >> he was quiet. he wasn't one that was dating, he didn't have a lot of friends. >> brenda strong is david's older sister. >> he wasn't into sports. he just was introspective. >> his mother shirley says david always knew exactly what he wanted to do. >> i am going to be in the army, an army man. that's what he said. >> how old was he when he first

started saying that? >> maybe 6, 7 years old. >> by 19 he had enlisted. he was stationed in upstate new york, and that's where he met joan. >> he was funny, he had a sense of humor and he was extremely shy. >> david was different than the other guys how? >> because he treated me a lot different. he treated me like i had value. >> which was something wonderful and new for joan. sexually abused at 12, abang donned by her patients. married to an abusive husband, having two children. then working in a topless club hooking up with the wrong men. then she met david. >> before the men had wanted you for sex, but that was it. this guy wanted you for you. >> he was willing to protect without controlling. he treated me like an equal. >> less than a year later, joan

asked david to marry her. >> i realized he was this really really great guy. and i didn't want anybody else to have a chance to find that out. >> in a small north dakota church, joan taft became mrs. david shannon. >> i thought he found somebody that was good for him. he was obviously happy. >> and she -- what was your impression of her? >> she seemed very nice, very sweet, very attentive to him, very much in love. >> they complimented each other, is what they did. >> it sounds almost as if you're talking about joan as if she was one of your children? >> she was almost like a daughter to me. yes. >> as for joan's two young daughters, daisy and elizabeth, david wanted them to be part of his new family. >> because he loved me, he loved them. >> and so he did. david shannon became both a husband and a father. >> they were all having a good time, being a normal family, you know, everybody getting along or

fighting as you do. you love them. definitely. >> soon the shannon's became six, with the birth of their two boys. and in 2000, david took the family south to fayetteville when he was transferred to ft. bragg. >> david loved the military, he loved being a soldier. you talk about somebody having a first love or something they love more than anything, he loved that uniform. >> and the military had been good to david. he was major shannon by now, well on his way to becoming a colonel. that was the phone call the shannon family was really looking forward to from ft. bragg. not the one they got in july 2002. >> they said, david's been shot, he's been murdered. no, it couldn't be. he was in special forces. he must have been into something odd. you know, there must have been something with what he was doing at work that -- this must have been a hit.

>> we felt that something had gone wrong. he found out something he was not supposed to have known. and that they had to get rid of them. >> it was so execution style? >> yes. >> somebody came in there with the intent of killing him? >> with the intent of killing him. >> here was an odd thing. there just wasn't any side of an intruder getting into the house. it was raining outside, remember. but nobody tracked any wet footprints inside. >> what she was telling us didn't really -- it just didn't really match up at the time. >> something else that didn't seem to match. stashed away in the bedroom were dozens of pornographic magazines and videos and a catch of sex toys. and when detectives asked what that was all about.

joan gave them a surprising answer. >> i told him that david and i were swingers. >> reporter: and suddenly the investigation turned on its heels and headed in a whole new direction. >> they would meet couples on the internet, and her husband would prearrange it, and then they would engage in some type of sexual relation with the couple itself. >> did that make your mind click a little bit? >> the person who shot david shannon might be familiar with joan shannon and the swinger lifestyle may have had something to do with that. >> finally a possible lead at the shannon's unusual sex life, created a motive for murder. coming up, an intriguing new lead. >> david actually said, you need to meet my wife janet. >> was there a fatal love triangle in this circle of swingers? when the mystery of the murdered major continues. rheumatologist

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while investigating the murder of david shannon, investigators discovered the couple was not as conservative as they appeared. did their complicated love life lead to his murder? >> they seemed from the outside at least, so ordinary. a military officer, good marriage, four attractive kids. murder investigations have a way

of shattering what seems to be. and now the shannon family's secrets were spilling out. >> of course you're going to have no idea what might exist behind the photo of family values. that's what detectives are for after all. they may have moved to the bible belt to fayetteville, north carolina. lots of churches here, there were also other activities that occurred at night. that had nothing whatever to do with family values. >> joan and david shannon were swingers. enthusiastic members of clubs whose sole purpose is to organize spouse swapping. as joan told the police, she and david had been swinging for years. long before moving to north carolina. >> but fayetteville after dark to their happy surprise, offered plenty of fresh opportunities to

discover a new lifestyle. >> he gets here and finds the location of a club. >> right off the bat? >> sure did, yes. >> it was as if this conservative bible belt state needed secret outlets for its more lurid desires. >> there were a lot of swinger sites. >> the swingers club david found was one of many in fayetteville, and this particular one catered to both couples and signals. >> how did that affect your marriage. >> i think it improved it, because so many marriages fall apart because someone cheats. it's not the sex, it's betrayal and lies. >> you both liked it a lot? >> we did. >> the shannons often met couples at hotels, sometimes they even brought them home. always trying to be discrete, of

course, but when the kids found themselves hustled off to a friends house for the weekend and came back to find their rooms rearranged, the older daughters had a pretty good idea something was different. was swinging somehow connected with what happened in their blood spattered bedroom? >> maybe there was some type of triangle here? >> i started asking questions about the couples they might have met, anybody that she was involved romantically with, that maybe her husband didn't know about, or did know about. >> did she offer anything? >> she identified a guy by the name of jeffrey wilson. >> jeffrey wilson? >> turns out david actually met him first online. jeffries was also in the army, based at ft. bragg like the major, he went by the name black

stump man. by now the deputy d.a. was monitoring the investigation. >> and they would online chat friends, chatting about the swinging lifestyle and that sort of thing. david actually said, you need to meet my wife joan, and invited him to a swinging party. >> they all got together at a local hotel, just social that time, no sex. >> there was a second swingers party that both of the shannons and jeffrey attended. at that party, he as well as others did have sex with joan. but after this happened, joan and jeffrey started seeing one another. >> that was okay, though. according to the rules, the shannons had established. as long as it was just sex and no one got romantically entangled. anyway, wilson was married with kids. and there was no indication that his wife knew what he was up to

on the side with joan. >> he started doing some one on one is what they call it, when the other person's not there. david always knew when i was with jeff. and the relationship with jeff started, it was sexual only. and in the process it developed into a friendship. >> sometimes joan even brought her new friend by the house, introduced him to her daughters. >> according to jeffrey and daisy, elizabeth, joan fell in love with him, told jeffrey she wanted to run off with him. this was no love affair, no matter what her curious daughters thought. she was emphatic about that. whether he knew it or not, she said, jeffrey was nothing more than a friend with benefits. but this never became a romance from your point? >> no, no. >> there wasn't really an emotional attachment? >> there was no love there. >> but now, of course, police needed to talk to jeffrey wilson. an affair was one thing, but now

wilson found himself caught in the middle of a murder investigation of a high ranking officer. >> coming up -- >> joan says, i can't take this any more, i want to be with you. >> might someone else have wanted david shannon dead? police are about to put more than one suspect under the micro scope. when the mystery of the murdered major continues. i just got my cashback match, is this for real? yep. we match all the cash back new cardmembers earn at the end of their first year, automatically.

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>> welcome back to "dateline" extra, in the case of the murdered major, one thing became abundantly clear, nothing was as it seemed in the shannon household. for starters, the army major's wife and mother of four was in a sexual relationship with a married man. once again, keith morrison. >> it was quite an eye opener. that is when joan shannon told detectives that she and her now dead husband were regular and enthusiastic swingers. when joan told them she developed a special one on one thing with a married man, jeffrey wilson. that was a real lead. could it be the victim was the

victim of a jealous lover. >> where was he when this murder occurred? >> he was working at the time of the homicide. >> a little checking revealed it was a perfect unasailable alibi. jeffrey wilson was innocent of murder, that is. as for a three-month affair with joan, wilson was very cooperative, he revealed every lurid detail. >> back in april they were probably meeting for sex about two times a week. and in july, the murder occurred on july 23rd, at least four times a week. >> now, the deputy d.a. began to flip that idea of a love triangle motive on its head. by the way jeffrey wilson was talking, it seemed to west, the person who had reason to kill david was not jeffrey, but joan.

>> from jeffrey's point of view, he describes how she was in love with him. that she was not in love with her husband. that she didn't want to be with her husband, that she could not financially afford to leave her husband. >> wilson said he kept telling her he was only in it for the sex. didn't want to run off with her. but if secret sex was all he wanted. joan kept pushing for more. >> the situation actually continued to escalate. i think it was around july 18th, and again, that would have been five days before the murder. jeffrey describes how he talks to joan and joan says, i can't take this any more. i want to be with you. can't we just run off together? >> david shannon knew, of course, that joan was seeing jeffrey wilson. after all, he invited jeffrey to join them in the first place. maybe he wasn't so happy about the cozy friendship joan seemed to be developing? that broke the rules.

>> david told joan that she could no longer see jeffrey because he could see that joan and jeffrey had become row manticly involved. i believe it would be sunday she's actually having sex with jeffrey wilson. and david is killed the early morning hours of tuesday. >> but if you ask joan, and, of course, we did. wilson just didn't understand. didn't understand that the affair was actually winding down. >> why would he say you were in love with him then? >> he's very self-centered and into himself and believes the world loves him. but i didn't. we were actually pulling apart because it was coming to the end. >> detectives added it up and here's what they had. a story about a shadowy intruder that didn't check out. the swinging, the affair, the story true or not that she wanted out of the marriage.

and oh, by the way, she stood to collect $700,000 in insurance money. the detective confronted joan, and she -- given her lifestyle, she said, she wasn't surprised at his attitude. >> he's disgusted. he's automatically prejudiced against me. and focuses on that, he's determined he's going to get me. >> back in north dakota, david shannon's family tried to keep up with all the shocking information. the murder, the revelations about swinging, and now joan was telling them she had become a suspect. to which they replied, joan? not a chance. >> we tried to play the scenario, did joan have a part in it? none of us can see that she could possibly have done that. it is just not in her nature to do that. she can't. >> but brenda did have somebody else in mind. >> now, elizabeth i could see

it. >> elizabeth, the shannon's 15-year-old daughter. is it possible she was a cold blooded killer who executed her very own stepfather? the man who adopted her, raised her, provided for her? maybe said david's sister brenda. daisy and elizabeth were always troubled. and when elizabeth hit her teens, watch out. >> david and joan did not have the tools needed to deal with what those two girls dished out. it was boys, drugs and violence. if she got angry with somebody, she would destroy something of theirs. >> that was hardly elizabeth's view of things. she conceded she was no angel, she acted out, all right, never denied that. but elizabeth always claimed it was the adults who made it ugly and hostile at home, where arguments, not affection were the family routine.

joan admits now, that she was overwhelmed by the task of parenting elizabeth, realized she was manipulated, easily and often by her daughter. >> and i gave up. i hate to admit it, but yes, i did. i gave up on that child. i didn't know what to do. >> so joan turned the task of parenting elizabeth over to major david, the military man, who did what he did to keep military order. >> he was definitely the tough one? >> he was the one that would decide the punishment. how long the grounding was going to be. >> a war of wills, david would ground her. elizabeth would escape. david responded with locks and alarms on her bedroom doors and windows. she squirted out anyway. >> what do you do if you can't keep your kids at home? you can't chain them.

>> clear message to david, you cannot control me no matter what you do? >> that's right. >> just a couple weeks before he was murders, david called home to north dakota to vent, ask his mother for advice, about dealing with that girl. >> i did ask him, would she do something? >> do something, what did you mean? >> do something vind, yes. he said, i don't think so. >> but you asked the question for a reason? >> i did ask him, yes, because i did not trust her. coming up, someone from inside the house that night steps forward. >> she was extremely emotional and she began to lay the facts on the table. >> and soon someone else is under arrest. >> it was another shock. >> when the mystery of the murdered major continues. (alert chime on phone) keep it simple

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returning to our story, once again, keith morrison. >> murder that most abhor end of crimes is shocking enough, but within mere days of the late major david shannon's sudden passing, the shocks resumed. as disturbing suspicions began to circulate and grow, and by the time they laid the major in the ground, the question of who did this dreadful thing seemed to be heading toward an early answer. it was elizabeth. david's family was convinced that rebellious elizabeth was so full of hate, she actually shot and killed her own stepfather. an opinion supported by several anonymous calls to the fayetteville, pa. >> we had crimestoppers, tips coming in, saying that elizabeth

shannon was actually bragging about the homicide. vera thompson was telling people about the homicide. >> remember her, she was elizabeth's best friend that was staying at the house the night of the murder. police braut her in for questioning. and this time they grilled her. >> she was extremely emotional. she didn't want to tell on anybody, and at that point in time, she began to lay the facts on the table. >> and oh, what facts they were. vera was elizabeth's buddy, her bff, they talked about everything. went everywhere together. >> and when she started bringing up facts that we were able to corroborate some of the information. >> vera provided plenty of supporting details, how just days before the shooting she went with elizabeth to a field and test fired the murder weapon. cops later found matching shells there. and how elizabeth dumped the gun

that night with a guy in the neighborhood named d. hum free. he was interviewed, he admitted it was true. >> everything was believable. >> then vera, just 15 years old, naive, frightened, no attorney representing her, dropped her bombshell. >> vera eventually became aware of -- through elizabeth that joan and elizabeth had had some discussions about killing david shannon. that her mother had attempted to poison david shannon. that joan shannon and elizabeth shannon had conspired to kill david shannon and it actually was elizabeth that had shot him that night. >> a conspiracy? joan the brains and elizabeth the braun? given tumultuous relationship between mother and daughter, who would have imagined they could

agree on anything let alone murder. it implicated both her best friend and joan shannon in a homicide. >> the arrest warrants went out for them simultaneously. joan shannon was arrested before elizabeth was arrested and before elizabeth gave any statement in the case. >> david's family was in fayetteville for david's funeral. right there when the cops came, saw what they did, joan had been paralyzed with grief, and then arrested. >> they put cuffs on her, i imagine they read her her rights right then, but i don't know. it was another shock. >> joan herself was unshakable in her insistence she did not do it. she had no part, she wore, in any of it. >> i might not be clear on that night, there's a lot i can't be clear on. but i know i didn't kill him. i know i didn't give elizabeth a

gun. i know i didn't try to poison him. and i know i didn't try to get anybody to kill him. >> though to police on the day of her arrest, she said nothing at all. on the advice of the lawyer appointed to represent her in the battle of her life. >> i found it difficult to believe she was involved in it, with the way she presented herself. very quiet, very passive, and joan insisted she had not solicited eliz breath to kill david, she loved david. >> and with an experienced attorney on the case. joan's loyal in-laws began to relax. >> once they finally started finding real evidence, they would know it was not joan. >> they would eliminate her? >> right. >> right. especially once the police arrested elizabeth. but there was a little problem. elizabeth had quite suddenly disappeared. coming up, the hunt for

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now with the conclusion to our story. here again is keith morrison. >> on the outskirts of fayetteville, north carolina, is

an old mobile home park. quiet, wooded, secluded. and in the summer of 2002, it had a new resident. elizabeth shannon was holed up in a trailer here hiding. >> we received a call saying that she was at such and such location. when we entered the home, we found her hiding, you know, underneath a futon in the living room. >> they arrested her, took her downtown, read her miranda rights and then questioned her without an attorney. at the time elizabeth, remember, was just barely 15 years old. and what did she say after two hours in that room? >> i told the story. >> the whole story? >> uh-huh. >> elizabeth confessed it all. every grisly detail of that awful night in the shannon house. assuming, that is, that what she told the detectives was actually true. >> it got to the point where i finally did for her.

but it never would have happened without her. >> her. her very own mother joan shannon. she insisted her mom had wanted david dead for months. first by trying to poison him. then later recruiting one of liz's friends to kill him. and finally -- >> she was like, would you be brave enough to do this? >> to do what? >> she wanted me to kill my step dad. >> in 25 years on the job, detective murphy had never heard a story quite like this. he pressed further, he said, pushing elizabeth to explain how her mother talked her into murder. and the answer, elizabeth says now, was this. it was love given and withheld. >> it wasn't an affectionate home overall. i wanted, like, a real mother/daughter relationship and it was never really there. >> several months priority the

murder itself, they were going out, they were actually being a family. there was some type of parental involvement. >> and she liked that a lot. >> she liked it. that was something she was lacking. >> but having finally offered her daughter the maternal affection she so craved? joan threatened to withdraw it unless she got that gun and used it to kill her father, or so elizabeth claimed. >> sounds crazy at first, but when somebody is in your year let alone your mother every day, it got to the point it was just normal. i just want to do this so nothing changes between me and her. >> and so elizabeth said on that night she took one of her stepfather's many guns, arranged ahead of time for a way to get rid of it, and waited while her parents watched their movie and fell asleep. >> she walked into the bedroom, placed the gun over her father's head, squeezed the trigger.

then she placed the gun to the chest and she fired the second round. >> as far as prosecutor billy west was concerned, elizabeth's tale had the ring of truth. >> i think she did it at the behest of her mother and in some respects to please her mother. >> so in exchange for her testimony, the da offered liz a deal. instead of life without parole, she could plead guilty and get a sentence of 25 to 31 years. >> we felt that was appropriate. offered joan the same plea deal that elizabeth had been offered. so that offer was extended by the state. >> no, i wasn't going to do it. >> why not? >> because when you're innocent, you're not going to say you did something that you didn't. >> besides, as victim david shannon's own mother and sister insisted, elizabeth was a devious and manipulative liar. especially when she got herself in a jam. >> so it didn't sound surprising

that liz would try to set up her mom like that. because as a child, if there was trouble, liz was usually there. but she always had to share the blame. >> she blamed somebody else? >> oh, yeah. >> even if she was caught red handed? >> absolutely. elizabeth always shared the blame. >> so now joan shannon's fate would be decided by a jury. da billy west told them about joan and david's swinging lifestyle. joan's affair. jeffrey wilson's claim she wanted to run away with him financed with insurance money from david's death. then there was the allegation that joan tried to poison david. and testimony from a young man who insisted joan asked elizabeth to recruit him to commit the murder and dispose of the gun. but the da saved his star witness for last. 15-year-old elizabeth shannon herself who told the jury that joan used a truly devious weapon.

maternal love given and withdrawn to manipulate her into murder. >> i can take responsibility for my role in everything. but she was trying to put everything on me. that's the point i kind of woke up and realized, like, let me just tell the truth. >> was it true? on the stand elizabeth's accusation was clear and powerful. >> throughout the whole thing while i was testifying, she couldn't even look at me. >> joan did not testify. she sat quietly and listened as her attorney portrayed liz as a liar and ruthless killer who acted entirely alone when she executed her stepfather. >> she is absolutely cold-blooded. she is entirely self-interested. >> elizabeth? >> she hated joan. she hated her parents. she wanted out. freedom. she would have done anything. when she killed david, she

killed the only disciplinary she'd ever had. then she made a deal to get herself out of it. >> the idea that joan manipulated elizabeth wasn't even possible, said the defense. certainly not for either of her parents. >> they couldn't keep her in school. they couldn't keep her in the house. they couldn't get her to do anything. then all of a sudden joan's going to get her to turn around and kill david? >> the jury deliberated a day and a half. then -- >> they came back guilty. >> my heart dropped. you go numb. it's like, so many things flash through your mind and you just realize life as you know it is gone. >> it was so unbelievable. we knew joan was innocent and she'd just been found guilty. it shattered our world in so many ways. >> joan shannon will spend the rest of her life in prison for orchestrating the murder.

she has no chance of parole. no more appeals. and elizabeth who actually pulled the trigger? she, too, was sent to prison for at least 25 years courtesy of the deal she cut with the da. >> i told the truth from day one. i wouldn't gain anything by lying. i would just sabotage my own life in the process. it doesn't make sense. >> they are in separate prisons now. two hours apart by car. but really a world away. we asked if they wanted to speak to each other, make peace, perhaps. look at our camera, we suggested. speak from the heart. >> i still love -- i still love you, elizabeth. it's very complicated. it's very difficult. you're still my daughter. and i know the situation is hard for both of us. and i am sorry i wasn't a better mother. i can't go back and change that.

>> but elizabeth didn't like this idea. >> i don't have anything to say to her. because it doesn't matter what i say. it's like she's not going to change. she's not going to tell all these people that she lied. >> in the years following their father's death, joan shannon's two sons, david's sons, were living in north dakota and grew up in the major's boyhood home here in little langton. his mother became in joan's absence their mother and grandmother. the boys believed in joan's innocence, visited her sometimes, and talked to her on the phone. they were not speaking to their sister. and major david shannon, his remains will spend eternity here just down the road from home in the old military graveyard under the black prairie sod and the wind. >> that's all for this edition

of "dateline extra." i'm craig melvin. thanks for watching. ♪ this is a tragedy on top of a tragedy now. >> it happened so quickly. their parents in the backyard spa. their mom in trouble. >> my dad just panicked. >> a sudden slip. a fatal fall. >> you're losing your mother. you're watching her go right in front of you. >> someone else was watching her too. a curious neighbor just moments before witnessed something astonishing. >> it was scary. the look on his face was almost