tt4w`t+o@p47" hnt& s'\ tt4w`t+o@p47" iztq 9n$ tt4w`t+o@p47" jntq +>d tt4w`t+o@p47" lzt& 3s8 i had always wanted since i was a little kid, i'd see these older couples dancing. every step was perfect and every move was in unison. they were one. >> richelle shetina was looking for the perfect partner in dance and in life, and she thought she found him in a wealthy doctor. >> he was a wonderful dancer,

my name's joseph. >> reporter: but somebody else wanted to cut in. this plastic surgeon. >> hello. i'm dr. mike dixon. >> 911, what's your emergency? >> reporter: three people trapped in what would become a dance of death. >> there's a bullet. i need somebody to hurry. >> there are police cars everywhere. there's crime scene tape all around. it was just absolute chaos. >> it was an in and out job, a hit to kill this person specifically. >> reporter: tonight only on "20/20," the woman caught in the middle between two doctors. >> the kind of plot you expect from a soap opera. >> this is the oldest story in the book. this is vengeance. this is revenge. this is pride. >> reporter: a dangerous game of cat and mouse. >> accused of hiring a hit man -- >> so there was some kind of a triangle things going on. >> reporter: but who's the cat? >> no part of this is right. >> reporter: who's the mouse? >> this is a huge whodunit. >> reporter: a case with no shortage of suspects. a list of ex-girlfriends.

and a con man with his own obsession. >> i'm kind of a sassy smart [ bleep ] and we just kind of hit it off. >> reporter: characters so villainous even their own children turn on them. >> you made yourself a monster, dad. >> the verdict is in. >> unanimous verdict. >> what was your mindset going into that first trial? >> let's go get these guys. >> there are real sociopaths. sometimes they sleep in your bed with you. >> okay, game on. >> reporter: a last dance in texas. good evening. i'm david muir. >> and i'm elizabeth vargas. and tonight a love triangle that started in texas and went on to make national headlines. two doctors and a beautiful woman who says she finally found the love of her life. >> but right here tonight what you have never heard until now. that woman caught in the center now speaking out. ryan smith with a story that went from dance lessons to dirty tricks to deadly consequences. >> reporter: on a lazy summer afternoon in lubbock, texas --

neighborhood of stately homes. >> somebody has broken a window in the back, and the doctor did not show up for work today. >> reporter: prominent local physician dr. joseph sonnier is found murdered. a landscaper finds his body. >> oh, no! oh, god. >> ma'am, ma'am. what's going on? >> reporter: shot and stabbed multiple times. >> there's a bullet that was laying on the ground. i need somebody to hurry. >> yes, ma'am. >> reporter: zach johnson, a detective with the lubbock police, heads to the scene. this neighborhood had to be freaked out by this killing. >> they were. they were very scared because this doesn't happen. especially to somebody that's so esteemed. >> reporter: upon entering sonnier's house it's immediately clear to detective johnson that this isn't a robbery gone bad. >> there was artwork in the home. there were very expensive pieces of furniture.

things, just kind of laying around. you know. nothing was taken. it was an in and out job. >> reporter: in the dining area johnson can see where the fatal blows were delivered. >> and the crime scene was very succinct. it wasn't spread out. you had the overturned chair. you had the glass on the floor. and you had the casings. so you knew that he was shot right here. >> reporter: another clue stands out. a gatorade bottle lies on the floor near the shell casings from the bullets. police determine it's a crudely fashioned silencer. >> we were dealing with something that was a hit of sorts, that somebody had come to this house to kill this person specifically. >> reporter: but who? >> to me it was just mind-boggling. you know, why is this man dead? he's a well-respected citizen in this community. why is he dead? >> reporter: sonnier's children are devastated and perplexed. two years earlier their mother had been murdered.

for sonnier's oldest son, dallas, it's a hauntingly familiar scenario. >> i knew how to plan a funeral. i knew how to scrub blood off the floor. i knew everything we had to do because i'd already done it once before. >> this just doesn't happen. >> the statistical likelihood that both parents would be murdered, separate occasions, is unfathomable. i got the call the day before the two-year anniversary of my mother's death. i thought maybe it had something to do with her death. that's how out of left field and completely out of nowhere this was. >> reporter: for joseph's third son, phillip, there are more questions than answers. >> we started racking our brains, well, it's got to be situation. if it's not a robbery, it's somebody he knows. >> reporter: this all took place in lubbock, texas. nestled in the heart of ranching country.

of cotton fields, cattle, and money. >> you can't see better sunsets and sunrises and thunderstorms and everything else coming in. but it's the people that drive it. there's no better people probably anywhere in the world. >> reporter: one of those people is the victim, joseph sonnier, a well-known doctor, successful businessman, and multimillionaire. and as far as women in lubbock are concerned, unquestionably a catch. he enjoys foreign travel, has a six-figure wine collection, and even makes his own perfume. >> he was a single man in his late 40s with disposable income and an empty house. >> he's living the single life and having a fun time. >> so it wasn't about getting married? >> i don't think he would have gotten married again. >> reporter: at 19 sonnier married his high school sweetheart, becky. dallas recalls his happy childhood, with loving parents.

>> my dad was the most supportive person in my life. my mom was our emotional support. >> merry christmas. >> reporter: . >> he was the one who was going to push us to succeed, push us to follow our dreams. >> reporter: dallas remembers how his father fell apart when his mother walked out on him after 27 years of marriage for another man. >> she was the only person that he had ever been with and ever dated and ever fallen in love with. when they got divorced, it was a shock to him. everything he'd worked for in his life evaporated in one second. >> reporter: his ex-wife, becky, quickly remarried, and to the sonnier family's horror she was murdered by her new husband, who then killed himself. james sonnier remembers how his father helped him and his brothers come to terms with their mother's murder. >> he came in after she was

guide about how to handle this -- this tragedy. >> reporter: and the elder sonnier was still in the process of rebuilding his own life. 48 years old and on the dating scene, dr. sonnier takes a chance. >> he went i think on a lark to a dance class. ballroom and salsa. swing. and through that dance community he found his confidence again. >> reporter: and that's not all he finds. >> he started to meet beautiful single women, attractive women who were also in his age range. >> so that's how he was able to start dating again. >> and he got the mojo back like that. >> so how did you feel about the women that he dated? them. >> reporter: dallas and his brothers had grown up and moved away. but every fall they joined their dad for a texas tech football game. one year dr. sonnier brings a date to their family tailgate. >> she's blond. she's tall.

>> reporter: she is richelle shetina. single mother of four boys who sonnier meets at a ballroom dance class. >> it's the first date and he's bringing you around his family. which is -- that's nerve-wracking for some people. >> i mean, it was the first date. it really wasn't a big deal to me. i certainly wasn't nervous about it. >> she knew how to handle herself in a social situation, around his sons. we're tough critics. you know. and we gave her a thumbs up. >> reporter: like sonnier, richelle is divorced and has grown children. they begin dating. and when things start to get serious, he takes her to visit his grandchildren in los angeles. >> touch your head. >> we had a great time. she came over to the house. played with my kids. it couldn't have gone better. >> she's a smart girl. >> reporter: while sonnier is enjoying dating richelle, dallas says his father's feelings do not run to marriage. >> in your mind he was never going to put a ring on it. >> that's right. >> reporter: but richelle may

according to sonnier's family she repeatedly tells him how much she wants to get married. >> it was constant pressure at every step of the way following the l.a. trip. >> that's not true. what i was looking for was a committed relationship with a good person. and that was it. >> reporter: a couple of months after the l.a. trip dr. sonnier tells his son that he and richelle were going to paris. >> it was a birthday gift for my 50th birthday. i was just over the moon. it was really a dream come true. >> reporter: joseph and richelle's romantic getaway includes a trip to the pont pont des artes, a bridge across the seine river with locks by the thousands. >> we bought a lock and joseph wrote his name on it and i wrote my name on it, and you throw the keen into the seine river. and that locks the most forever. >> reporter: but for richelle

a matter of weeks. on a sweltering wednesday in july richelle learns that the love of her life has been murdered. >> there are police cars everywhere. there's crime scene tape all around joseph's house. emergency vehicles there. reporters there. it was just absolute chaos. >> reporter: searching for a killer, the first place police go is to the people closest to the victim. so detective zach johnson's attention turns to sonnier's girlfriend, richelle shetina. >> meeting with richelle that very first time i don't know a lot about her. >> did you ever have a time where you suspected that richelle could in some way have been involved in dr. sonnier's death? >> you always have to consider people the closest because 90% of the time it's going to be the people that are closest to our victims that committed crime against them. >> reporter: the police take richelle in for questioning. she's on the hot seat, and she

>> there's just, you know, some girls that he dated. and joseph would get these horrible text messages, you know, calling him [ bleep ]. you know, you're such a [ bleep ], whatever. >> reporter: when "20/20" returns. hey, you forgot the milk! that's lactaid. right. 100% real milk, just without the lactose. so you can drink all you want... ...with no discomfort? exactly. here, try some... mmm, it is real milk. see? delicious. hoof bump! oh. right here girl, boom lactaid . 100% real milk. no discomfort and for a creamy and delicious treat, try lactaid ice cream not all wrinkles are the same. some wrinkles, like the vertical ones... make you look sad. revitalift from l'oreal even fights the appearance of tough vertical wrinkles. it works! the advanced formula with pro-retinol visibly fights wrinkles plus firms skin. revitalift from

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>> announcer: "20/20" continues with "a last dance in texas." joseph sonnier, a respected

home in an upscale lubbock neighborhood. and the first person homicide detective zach johnson wants to interview is richelle shetina, sonnier's current girlfriend. he brings her in for questioning. >> how would you describe your relationship with dr. sonnier? >> he's -- he's the love of my life. >> meeting with richelle that very first time, i don't know a lot about her. there were a couple of things that were mentioned by her that struck me as odd. >> reporter: richelle tells detective johnson that in the months leading up to the murder she feels like someone was watching her, following her to the gym. >> i had gone in to work out and i pulled into the parking lot and there was this big creepy-looking guy sitting there. and at the door, like he was looking for someone or watching someone. >> reporter: she also thinks someone was hiding in sonnier's back yard, spying on the couple one evening after dance class.

joseph and i both saw a flash from the outside. we laughed and kind of joked about, you know, maybe somebody was following us. >> reporter: detective johnson asks richelle if she knows anyone who might have stalked the doctor or held a grudge against him. >> joseph would get this -- these horrible text messages, you know, calling him a [ bleep ] and you know, you're such a [ bleep ] and whatever. >> reporter: and richelle has no shortage of theories about suspects. she rattles off a list of sonnier's ex-girlfriends. she also remembers a letter she received from a mysterious woman named tina. >> and that she met joseph on the internet and that they had sex for money, basically. and he said, you know, this is obviously someone trying to drive a wedge in between us. >> reporter: police are intrigued by the idea of a love rival. but instead of focusing on sonnier's dating history he asks

one name is on the tip of her tongue. >> his name is thomas michael dixon. he's a plastic surgeon in amarillo. >> reporter: dr. mike dixon. >> hello. i'm dr. mike dixon. if you're considering plastic surgery -- >> reporter: well known, he's divorced, wealthy, and used to date richelle. >> he had a place in amarillo and i went there to get botox injections. >> what attracted you to him? >> he was funny, he was very witty, and he was enjoyable. if it can be enjoyable to have somebody put needles in your face, you know, i guess that's be. >> reporter: richelle and dr. dixon had dated for a year and a half before they broke up and she started seeing dr. sonnier. >> did he know about your current relationship? joseph. he called him by name in a series of text messages, trying to get me to go out with him and to meet him for coffee. >> reporter: richelle says she rejected his advances but he was

>> so he wanted you to see him on the side, basically? >> he wanted me to come back to him. i told him no. >> reporter: but is dixon the kind of man to take no for an answer? johnson wants to find out. so he drives two hours to amarillo for a face-to-face conversation with richelle's ex that the detective secretly records. [ knocking ] >> dr. dixon, i'm detective johnson with the lubbock police department. we've got a case down in lubbock, and i'm needing to talk to you about it. >> i told him, it's richelle's boyfriend. and his first thing was oh, i don't know anything about him. >> i don't know anything about him. i haven't talked to her in months and months. >> and i was like, okay, well, that's a little odd because in our interview with richelle she told us that he knew about the relationship. >> yeah, i'll be honest with you. i loved, loved, loved that woman. i really did. >> he was obsessed with richelle.

over this break-up. he just couldn't seem to let her go. >> for detective zach johnson alarm bells were sounding. >> i really had fallen head over heels. in fact, made a lot of life changes for her. >> he's very up front about yeah, i wanted her back. >> reporter: dixon recalls how their relationship ended when he failed to propose to richelle on her birthday and instead gave her a subscription to a tea of the month club. >> and she went ballistic and said, well, it -- i mean i remember clearly it's not a big [ bleep ] rock. and i said, no, it's not. like a wedding ring. >> it wasn't about the fact that it was tea. tea is lovely. i don't happen to drink it. he was not present in any emotionally supportive aspect of my world. >> reporter: but despite richelle's unhappiness with him dixon says they kept in contact after their break-up, exchanging texts and he says they even planned a weekend getaway to a resort. >> she was like, hey, do you

and i was like, yeah, i do. and so let's plan a trip, blah, blah, blah. the next day she's like, hey, sorry, i'm in love with my dance partner. >> he still loves her. he's got a lot of feelings for her. but boom, she drops the hammer on him and says oh, by the way, i'm in love with my dance partner. >> some would say, well, you're throwing it in his face a little bit. >> well, no, i wasn't throwing it in his face. there was an ugliness from him to me. >> reporter: dixon seems like a likely suspect, but he has an alibi the night of sonnier's murder. as do richelle shetina and those ex-girlfriends. detective johnson is stumped. >> there's something not right here. this is a huge whodunit. >> reporter: until johnson gets the call all detectives pray for. it's from a tipster who offers a new name that could crack the case. >> his name's dave shepard. s-h-e-p-a-r-d. >> reporter: but who is dave shepard? stay with us.

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tt2w`t2n`qt" bt@q2;x tt2w`t2n`qt" "a@q"7< tt2w`t2n`qt" bm@q)> announcer: "20/20" continues with ryan smith and "a last dance in texas." homicide detective zach johnson is desperately trying to unravel a tangled web, but he has no viable suspects in the murder of dr. joseph sonnier.

what was it that broke this case wide open for you? >> when paul reynolds called the police department. >> my name is paul reynolds. i'm trying to get some information and we think we've got a crime that happened down here in lubbock. it's a homicide. >> who is paul reynolds? >> believe it or not, there are good people in the world and paul reynolds is one of them. >> reporter: reynolds is a registered nurse. down on his luck when a childhood friend named dave shepard offers to let him crash on his couch. he offers to tell police everything he knows. >> so i crashed on his couch. he kind of started in with just weird talk. >> reporter: according to reynolds, shepard starts acting strangely, telling wild violent stories of killing a man in lubbock. incredulous, reynolds googles the information, only to discover that the murder is real. >> and then these stories started to come out. >> reporter: reynolds tells investigators that coincidentally, shepard is a

richelle's ex, dr. mike dixon. the investigation takes a turn, zeroing in on shepard. >> and tell me about y'all's relationship, how it evolved. >> he's quick-witted. i'm kind afd of a sassy smart [ bleep ] and we just hit it off. >> they bonded over cigars and martinis at local hangouts in amarillo commiserating over ex-wives. >> smoking cigars is a very sociable thing and we just connected, hooked up. >> so y'all just happened to meet up in the cigar shop -- >> that's it. and kind of had a connection. >> reporter: shepard's daughters, haley, abigail, and rachel speaking exclusively to "20/20" about the strange bond between their father and dr. mike dixon. >> dad was definitely obsessed with mike. >> really? >> he had a big man crush on mike. >> reporter: it was an unlikely bromance. dixon, a successful plastic surgeon, and shepard, a divorced unemployed con man. >> so what did your dad see in him?

and his success. >> dad wanted to be mike. >> reporter: shepard may have been obsessed with dixon, but dixon was obsessed with someone else. richelle shetina. >> he left his wife for her. you know, she broke up his marriage. and he just wanted i guess payback. >> david shepard does come in and tells us exactly what happened. >> so he tells you everything. >> this whole thing was like this stair step, and it started at the very bottom of these stairs as being a prank. >> reporter: shepard tells police that it all began harmlessly enough, trying to tarnish dr. sonnier's reputation in the hope that richelle would break up with him and run back to the arms of dixon. what were some of the things they came up with? >> they were going to get this porn subscription, like child gay important, and they were going to send it to dr. sonnier's office.

buy the most obscene, nastiest, man-boy love association book he could and buy him a subscription and send it to his office. because -- i said that's a gift that'll keep giving. >> they were thinking that was going to ruin his reputation, his professional reputation. >> reporter: thinking more like teenagers than grown men, they concoct ridiculous schemes to humiliate dixon's rival, like hiring a stripper to pretend to be sonnier's girlfriend so that richelle will think he's two-timing her. as the months go by and richelle is still dating sonnier, dixon becomes desperate. >> he said we have to follow him. we have to figure out where he's at. he goes, hey, what are you doing? let's go -- let's take a little trip to lubbock. >> reporter: they drive the 120-mile stretch of highway between amarillo and lubbock. >> and next thing i know he tells me that richelle and dr. sonnier take these dance classes. and he showed me where the dance class was, where to go. >> reporter: shepard spends

lovers. turns out it was shepard who scares richelle in the early morning hours when he's staking out her gym. and it's shepard who in a brazen move breaks into sonnier's back yard and takes this accidental selfie. the flash alerting richelle and sonnier inside. >> it looked like a camera flash. and we kind of shrugged our shoulders and said that was weird. >> reporter: shepard fails to dig up dirt on sonnier. so dixon grows impatient. >> was there a specific act that he was wanting done that -- was that what y'all were discussing? >> yes. >> and what was that? >> he -- he wanted him hurt. and then it gradually developed into having him killed. >> reporter: after hours of interrogation an exhausted shepard gives police a blow by blow of what happened that night. a full confession. july 10th, 2012 is the last night shepard will stalk his prey.

yard armed with a gun and a knife and lies in wait. sonnier comes home, makes himself a drink after a long day at work. suddenly, shepard is at the back window. >> i pull the gun out of the bag with the gatorade on it. i point the weapon with the bottle at him. >> reporter: shepard pushes through the window and fires, emptying his gun into sonnier. the doctor somehow finds enough strength to stumble out of the room to get away. but shepard is in pursuit and finds him in the garage, where he stabs him 11 times. >> he's laying on the floor, not moving, not breathing, nothing. i check his pulse in his neck. he's dead. >> reporter: there's so much blood it seeps under the garage door to the outside. >> he's a murderer. he's a liar. he's a thief. he's an embezzler.

as far as his role in this, i think he was a pawn for mike dixon. >> reporter: so district attorney matt powell offers shepard a deal. rat out his good friend dr. mike dixon in exchange for a life sentence instead of a death sentence. but who will the jury believe, a respected plastic surgeon or a convicted con man? and would one of them not live to tell? big news! the new sprint lte plus network is faster than verizon and at&t... based on data from the world's foremost authority on independent measurement. cut some prices in half. switch to sprint and save 50% on verizon, at&t or t-mobile rates. no gimmicks. it's the biggest offer in u.s. wireless history! what about verizon? 50% off. at&t too? 50% off. even t-mobile? 50% off. plus, we'll even pay your switching fees, up to $650 per line. so start the new year off right and switch today. does your baby's diaper make them feel like this? unswaddle them and set them free with huggies little

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>> announcer: now more of "20/20" and "a last dance in texas."

rolling across the outer western plains, in downtown lubbock things were heating up as the biggest murder trial this town has ever witnessed kicked off. surgeon. >> dr. michael dixon -- >> accused of hiring a hit man. >> friend and business partner david shepard. >> i cannot believe that they did this. it makes me so angry. a lowlife scum and a piece of [ bleep ] doctor. >> reporter: when dr. mike dixon was arrest kd and brought to trial for his role in joseph sonnier's death, dallas sonnier was hellbent on bringing his father's suspected killers to justice. >> what was your mindset going into that first trial? >> let's go [ bleep ] get these guys. >> reporter: but as always, there's another side to this story, and there was another son in that courtroom. >> he was a good dad. he still is a good dad. >> reporter: andrew dixon convinced his father is innocent. >> they're trying to prove him guilty, and he's fighting for his life. i mean, it's just terrifying and just so sickening. >> reporter: the man tasked with

away, a hard-charging texas district attorney named matt powell. >> mike dixon's running the show and he orchestrated this whole thing. >> many people make the argument that mike dixon never laid a hand on dr. sonnier. >> he's just controlling the -- dave shepard's just another instrument for mike dixon. >> reporter: and that instrument dave shepard has agreed to testify. pitted against his friend mike dixon to avoid the death penalty. >> this is the oldest story in the book. this is vengeance. this is revenge. this is pride. >> reporter: the motive? in courtroom 72 of the lubbock county courthouse the prosecution paints a picture for the jury of dixon as an obsessed, calculating puppetmaster. >> he wanted her to suffer or he wanted her back. he knows what the true answer to that question is. but dr. sonnier was in the way. >> reporter: the pillars of powell's case -- police find the gun shepard used at the bottom of a lake, conveniently located behind dixon's office. and discover it's registered to

and they also find surveillance videos from the day after the murder. that's shepard in the plaid shirt, dixon in blue. the two hanging out. thick as thieves. >> was there any discussion about when the police went over there and spoke to him? >> he was nervous. he said i had to get out of town. >> reporter: but he didn't. instead shepard attempts suicide. he slits his wrists. when he fails, who does he call for help? his buddy mike. here they are. that's shepard towering over dixon as they head into the doctor's office to stitch shepard up. >> so he sews your hand up. does he discuss anything with you in reference to sonnier? >> he told me i need to keep my cool. >> reporter: prosecutors also have a myriad of incriminating text messages between shepard and dixon. as shepard stalks sonnier for months. messages from dixon ordering shepard, you have to stay close, watch him in the a.m., go get 'em.

finally, what's the price for murder between friends? police say dixon paid shepard for the hit in the form of a box of cuban cigars and three silver bars. bars that turned up at this pawn shop in amarillo. one before the murder, two the day after the murder. sold by none other than dave shepard. >> in terms of demeanor he didn't strike you one way or the other, it sounds like? >> not at all. >> couple days later he's on the front page of the paper. >> i was blown away. >> reporter: but dixon's lawyers have an explanation for all of this. first the gun used. they say shepard stole it from dixon's home. defense attorney frank sellers shows me where. >> they came in here. they're picking out a cigar to smoke. and shepard opens this drawer here, and it's a gun. >> so that's how shepard knew a gun was in that drawer. >> exactly. >> reporter: and the silver bars? the defense says they were for a business investment, not a murder for hire. they say dixon only wanted shepard to try to take photographs of sonnier out with other women to show richelle

cracked up to be. >> in the days before they leave for paris he says, "it's got to happen tomorrow because the trip is imminent." it almost sounds like somebody's trying to say attack or hurt somebody imminently. >> we believe it was an attempt to make the trip uncomfortable. get the photographs. >> reporter: and they say this was all because dixon was upset. he believed richelle was throwing her new relationship in his face. >> richelle was posting on facebook all the time how dr. sonnier was ten times the man that michael dixon would ever be. and he wanted to show richelle that she was wrong. >> reporter: zbl so from your perspective it wasn't about richelle shetina. ego. >> right. if he was obsessed with her, he'd have been following her. >> were you in any way trying to flaunt your relationship? >> he was blocked from my facebook page. no. >> reporter: dixon's attorneys say dave shepard simply went

>> do you at least admit that he planted the seed by even discussing this relationship? >> planted the seed for a murder? no. absolutely not. >> mike is morally responsible for david shepard being down here. but not for the purpose of killing dr. sonnier. mike dixon never wanted that to happen. >> i asked him, you sure you want to do this, mike? i said, when you kill somebody, that will affect you for the rest of your life. you'll have nightmares. it will bother you. and he goes, "doesn't bother me." >> reporter: and when it was time for the trigger man to testify against his best buddy family was sitting front and center. >> he had a chance to get up there, confirm his story, point to that guy as the person who paid him to kill my dad, and end it all. >> reporter: he does end it.

shepard is about to drop a bombshell. >> but daddy, why didn't you tell that? >> reporter: and make his own flesh and blood despise him. >> you've made yourself a monster, dad. >> reporter: when we come back. i'm jerry bell the second. and i'm jerry bell the third. i'm like a big bear and he's my little cub. this little guy is non-stop. he's always hanging out with his friends. you've got to be prepared to sit at the edge of your seat and be ready to get up. there's no "deep couch sitting." definitely not good for my back. this is the part i really don't like right here. (doorbell) what's that? a package! it's a swiffer wetjet. it almost feels like it's moving itself. this is kind of fun. that comes from my floor? eww! this is deep couch sitting. [jerry bell iii] deep couch sitting! performance... ...reimagined. style... ...reinvented. sophistication... ...redefined. introducing the all-new lexus rx and rx hybrid. agile handling.

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>> announcer: "20/20" continues with ryan smith. when the convicted murderer dave shepard took the stand at his best friend mike dixon's trial, he was facing the victim's family, the jury, but perhaps most poignantly his three daughters, rachel, abigail, and haley. and they are not here to defend their father. >> you were in that courtroom to

>> we were there more in support of the sonnier family. >> right. >> yes. >> our heart was broken for them. >> reporter: shepard's daughters saying their father is a murderer. >> and do you think that mike dixon paid your father to kill dr. sonnier? >> yes. >> yes. >> reporter: but on the stand a shocking twist nobody saw coming. >> shepard himself has basically denied all of his previous testimony. >> reporter: shepard's confession was expected to put mike dixon away. this is what he said. >> i said, well, just go behind him when he's not paying attention, hit him with a board. i said, you could probably kill him. and doc went -- like that. we'll talk about that later. >> reporter: but in the courtroom he suddenly changes his story and says mike dixon never asked him to kill sonnier, letting his friend completely off the hook. >> you begin to question him. what happens? >> well, he completely digressed from what his statement was to law enforcement in the fact that mike dixon didn't have any involvement in this deal.

prosecutor blindsided. >> what's going through your mind? >> okay, game on. >> in that moment i've never hated anyone more than i've hated him in my entire life. >> reporter: the shepard daughters also watching are embarrassed and ashamed. >> it was cowardly. >> i mean, he has a chance to make it right and he completely ruined it. >> why do you think he did that? >> he was trying to help out his buddy. >> reporter: the girls compelled to do something extraordinary. they apologized to the sonnier family for what their father has done. >> what did you say to them? >> we are so sorry for what he has done to you and what he's continuing to do to you. >> reporter: and after shepard changes his story, back in jail, his daughters confront him. it's a rare and raw look at a fractured family. >> but daddy, you didn't tell the truth. >> i did. >> you didn't say anything. you just kept saying that you wouldn't tell them. >> but i did. >> why didn't you tell -- no, you didn't, daddy.

i don't -- i'm not going to answer that. >> none of this is right. none of it will ever be right. >> there's nothing i could do. >> no matter what i do -- they think i'm some kind of a monster. >> you've made yourself a monster, dad. >> reporter: you were literally breaking down in tears. >> it was frustrating. i felt like i was scolding a child. like i just want you to answer my question and then you can go back to time out. >> reporter: but the damage was done. if shepard hoped to free his friend, it works. the case ends in a mistrial. >> the only reason for the hung jury was david shepard's testimony. >> reporter: regardless, d.a. matt powell is undeterred. >> matt powell comes into the room where we're standing, and without blinking he says, "we are going to get this guy. we are going to do this again. don't you worry. i've got you." and that's all i needed to hear. >> reporter: a second trial is scheduled, delaying a homecoming

once lived in this big texas spread with a canyon as his back yard. >> you look so happy. >> he was a good dad. he did dad things. you know, american dream kind of stuff. >> reporter: but that dream was over. the nightmare truth is andrew's father is facing capital murder charges and the second trial begins. >> amarillo doctor michael dixon is back on trial. >> reporter: and this time around prosecutor mike powell has a new witness. >> the number one most important thing from this second trial was the unbelievably courageous testimony of haley shepard. >> reporter: next, dave shepard's own daughter haley takes the stand. and what she recalls about a simple steak dinner will stick a fork in this case once and for

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what you do with it is up to you. tylenol . >> announcer: "20/20" continues with "a last dance in texas." lubbock, texas. haley shepard, the hit man's daughter, is on the stand. she takes the jury back three years. and you'll see why. it's a hot summer night in amarillo, texas. her father, dave shepard, treats his daughters to a fancy steak dinner, served with a side of suspicion. >> he had some money. i got a nice steak. >> reporter: shepard's daughters say that night their typically cash-poor father bragged about buying a new grill and new tires for his suv. >> dad had money out of the blue. he just randomly had money. and he didn't ever have money. >> reporter: for his older

brand new cell phone. >> we all asked him, how do you have money? and his words were "i did some work for mike and he paid me early." >> reporter: this time the prosecutor calls her, not her father, to testify in mike dixon's retrial. and you think that was a prepayment for killing dr. sonnier. >> in retrospect, absolutely. >> reporter: for victim joseph sonnier's family haley's testimony is a game changer. >> she got up there and said, at dinner i asked my dad, i said where did you get this money? and david shepard says to her, i did some work for mike, he paid me early, don't ask what i did for him. game over. >> reporter: it takes a new jury only three hours to deliberate. >> and my hand was shaking like this because i knew we got a i knew it. i knew it. i knew it. >> reporter: and he's right. >> the verdict is in.

>> guilty on two charges. >> reporter: mike dixon is convicted on two counts of capital murder. >> what was your first reaction? >> i had to turn to my wife, and i had to say, he said guilty, right? he said guilty? we'd been waiting for that moment for over three years. >> reporter: for the sonnier brothers it's finally closure. >> when you look at the photos of him, smug smile. when you look at his mug shot from his arrest, smug smile. and he has had that smile for both trials, and it was so great to be able to know that we'd finally wiped that smile off his face. >> reporter: still -- >> he's lost everything. time with his family. >> reporter: another son, andrew dixon, remains convinced his father is innocent. >> when you think about the fact that he has to spend the rest of his life in prison without

feel? >> it's unreal. it's like a nightmare. you lay your head down at night and it's just always there. always in the back of your mind. everything. >> reporter: remarkably, dave shepard's daughters have accepted both men's fate as justice served. >> i know you guys don't talk to your dad a lot right now. but if you could what would you say to him? >> we're doing very good. we are all okay. >> we're okay without him. >> i think he's where he needs to be. >> reporter: as for the woman at the center of it all, richelle shetina has a warning. >> there are real sociopaths and psychopaths that walk amongst us. they're charming. they sit at the dinner table with you and your children. and sometimes they sleep in your bed with you. they're not capable of feeling love for you or empathy for anyone. when you see that, don't ignore it. get out.

as fast as you can. >> reporter: tonight, richelle shetina has put mike dixon out of her mind but says joseph sonnier will always have a place in her heart. >> i would tell him i loved him. and that i'll always -- i'll always love him. and i would just tell him how sorry i am. >> both dave shepard and his one-time best friend dr. mike dixon are now serving life in prison without the possibility of parole. dixon's lawyers are appealing that verdict. >> and that is our program for tonight. but be sure to join us tomorrow night for a special "20/20" saturday. i'll have the very latest on the major new turn in the bill cosby case. i'm elizabeth vargas. >> and i'm david muir. for all of us here at "20/20" and abc news, thank you for watching tonight. and i'll see you tomorrow night. >> that's right.