>> when somebody you love is murdered, it is the very, very worst thing. and the only thing worse than that is when the person who did it gets away with it. >> this is a huge whodunit. >> who came into dr. joseph sonnier's house, shot him, and knifed him? >> how would you describe your relationship with dr. sonnier? >> he's the love of my life. [cries] >> we were dealing with something that was a hit, >> we started racking our brains. well, it's gotta be some type of girlfriend situation. >> a stalker... >> creepy looking guy and he was staring at the door, like he was looking for someone or watching someone. >> a confession...

a payoff... and a courthouse twist that nobody saw coming. >> everybody is stunned. stunned. >> it was devastating. i mean, i had a moment of just silence. i couldn't breathe. i couldn't >> i mean, you can't make this stuff up. that's one of the fascinating things about this. >> this is the oldest story in the book. vengeance, pride, revenge. >> today in lubbock, cooler temps that will dip into the upper 70s and lower 80s. >> a beautiful summer day in lubbock, texas. >> the landscapers start their usual routine at a doctor's house, but they're starting to think something's off. >> somebody has broken a window

in the back! the doctor did not show up for work today. oh, no! >> ma'am. what's going on? >> dr. joseph sonnier's body is in the garage. his murder is truly brutal. shot six times. stabbed 11 times. >> 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. >> detective zach johnson's first thought in a wealthy neighborhood is naturally, it's a robbery gone bad. but... >> there was artwork in the home. there were very expensive pieces of furniture. there was ipads, all kinds of things, just kinda laying around. you know? nothing was taken. it was an in-and-out job. >> pretty clearly it happened in the dining room. the window, the bullet casings. >> and that 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. >> and something else. a gatorade bottle near the expended shell casings. it's an amateur silencer, so this is not a robbery at all. >> we were dealing with something that was a hit, you know, of sorts. that somebody had come to this house, and to kill this person specifically. to me, it was just mind-boggling. why is this man dead? he's a well-respected citizen in this community. why is he dead? >> dr. sonnier, a wealthy pathologist with three grown sons, and of course, they're absolutely devastated. and it's even worse because two years before, their mother had been murdered by her second now their dad iskilled. >> 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 had already done it once before. >> 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. >> we started racking our brains. well, it's gotta be some type of girlfriend situation. if it's not a robbery, it's somebody he knows. >> the statistical likelihood that both parents would be murdered separate occasions is unfathomable. >> lubbock is in the middle of ranching country. big sweeping planes, cotton fields, wide open skies. there's money, at least in dr. sonnier's neighborhood. he's a well-known doctor. a multimillionaire. a businessman. he loves to travel and has an expansive wine collection. >> he never did the whole dating scene in college. he was married at 19. he married his high school

sweetheart. we all loved becky. >> merry christmas! >> but his mother falls in love with another man and leaves sonnier after 27 years. >> 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 was evaporated in one second. >> becky quickly marries the man, but to their horror, she's murdered by her new husband, who then kills himself. dr. sonnier's left with his sons. sonnier's 48 years old and dating for the first time since high school. >> he was a single man in his late 40s with disposable income and an empty house. >> in the beginning, he didn't

think anybody would want to date him. middle-aged man, he was bald. kept trying to tell him, "women don't care about that." >> he was still really nervous. he had been with my mom since he was 16 years old. >> i don't think he would have gotten >> he went, i think, on a lark to a dance class, ballroom and salsa and swing and things like that. he started to meet beautiful single women, attractive women who were also in his age range. and he got his mojo back just like that! >> so how did you feel about the women that he dated? >> the truth is, we liked most of 'em. >> richelle shatina is a divorced single mother. four grown boys of her own, and they meet at one of those ballroom dance classes. >> dallas and his brothers don't live in lubbock anymore, but every fall they come back for a family tradition, one of those

giant tailgate feasts at a texas tech football game. and one year, the doctor brings a date. >> she's blonde. she's tall. she's gorgeous. >> it's a first date and he's bringing you around his family which is, that's nerve-wracking for some people. >> i mean, it was a first date. [laughs] it wasn't a big deal to me. i certainly wasn't nervous. >> 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. >> richelle and dr. sonnier traveled to california to visit dr. sonnier's grandchildren, and that seemed to make her very happy. >> where's your head? >> head. >> we had a great time. she came over to the house. we played with my kids. it couldn't have gone better. >> it seemed like a good match. they got along really well. he seemed to be having fun. >> dr. sonnier, he may have been a little cautious about,

you know, jumping to marriage right away. >> his family thinks richelle wants a proposal. >> i'm not saying it would've been out of the question at all. i adored him. i loved him. >> so just so i have this clearly, you never asked joseph -- you never pressured joseph to marry you. >> no, we -- not one time did we have a discussion about marriage. >> dr. sonnier, for richelle's 50th birthday, decided to take her on a really big adventure to paris, the city of lights, where, you know, love is everywhere. >> i was just over the moon. it was really a dream come true. >> they went to the pont des art. that's the bridge across the seine, famous for love locks. >> we bought a lock. and joseph wrote his name on it. and i wrote my name on it. and you throw the key into the seine river. and that locks in the moment

forever. >> for rochelle and joseph, forever is only a matter of weeks. she gets a call that the man she says is the love of her life is dead in his garage. >> 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. >> of course, when there's a murder, especially when there's no robbery, the first people police check out are lovers, family, friends, so detective zach johnson is going to bring in richelle. >> 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? >> 90% of the time, it's gonna be the people that are closest to our victims that commit the crime against 'em. >> the police are looking for a motive. maybe rochelle is angry that

sonnier hadn't proposed. they ask where she was at the time of the crime, if she can imagine anyone who might have met the doctor harm. >> there's just, you know, some girls that he dated. joseph would get these horrible text messages, you know? calling him a [bleep]. and you know, you're such a [bleep] and whatever." >> then she mentions a name, someone who seems pretty unlikely as a murder suspect. another doctor, but one that lives in another town who never even met sonnier. one of richelle's ex-boyfriends. >> oh, she thinks she has... a stalker.

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>> dr. sonnier is dead. >> ma'am, if you will please state your name. >> richelle shetina. >> in that interrogation room, detectives want any scrap of information they can get from his girlfriend, richelle shetina.

>> how would you describe your relationship with dr. sonnier? >> he's the love of my life. >> rochelle tells detective johnson she thinks she has a stalker. she feels like somebody has been watching her, even 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 he was staring at the door like he was looking for someone or watching someone. >> a couple of weeks later, her and dr. sonnier are in dr. sonnier's house. and they're drinking wine, in the kitchen. and they see a flash. >> it was dark outside, and joseph and i both saw a flash from the outside. we laughed and kinda joked about, you know, maybe somebody was following us. >> shortly after that, dr. sonnier has locks put on the gate. he has his locks changed at his house. >> and another thing.

richelle talks about a letter that seemed to be from a girlfriend of sonnier's. she thought it was fake. >> it was from this girl who said her name was 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." >> well what kind of a motive do i have with her? do we have maybe a jealousy motive? do we have another kind of anger motive? >> so, maybe there's a rival looking for revenge, but in addition to asking about sonnier's past girlfriends, detective johnson asked richelle about her past lovers. and there's one name she brings up right away, her boyfriend right before she met dr. sonnier at the dance class. >> dr. thomas michael dixon. he's a plastic surgeon in amarillo. >> hello, i'm dr. mike dixon. >> he's well-known, married, successful, a wealthy doctor, and they meet when richelle is a patient.

>> he had a med spa in amarillo. and i went there to get botox injections. >> what attracted you to him? >> he was funny. he was very witty. you know he was enjoyable. if it can be enjoyable to have somebody put needles in your face, you know, i guess that's about as enjoyable as it could be. >> richelle and dr. dixon are together for about a year and a half, and dixon's wife ends up divorcing him because of it. then richelle starts seeing joseph sonnier. >> did he know about your current relationship? >> he knew i was dating joseph. he called him by name in a series of text messages trying to get me to go out with him, to meet him for coffee. >> so he wanted you to see him on the side basically? >> he wanted me to come back to him. i told him no. >> so i'm still trying to figure out what's going on. and i knew, well, we're gonna get a little bit more insight into this thing, we talk to dr. dixon. >> it's a two-hour drive to amarillo and he just goes

straight over to dixon's house, a straightforward face-to-face conversation, which johnson records. >> hi, i hate to come bugging you at your house at all hours of the night. >> what's going on? >> well, we've had a homicide in lubbock, texas, today. >> i told him, "it was richelle's boyfriend." and his first thing was, "oh, well, 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. he was havin' a lot of problems gettin' over this break-up. he just couldn't seem to let her go. >> i really had fallen head over heels. in fact, made a lot of life changes for her. >> he's very upfront about, "yeah, i wanted her back." >> dixon says their relationship

ended a while back probably because he didn't give her a diamond ring and propose on her birthday. instead, he'd given her a subscription to a tea of the month club. >> and she went ballistic and said it isn't... i remember it clearly, i said, "no, it's not." like, a wedding ring. >> when dixon talked to police, he talked about how he gave you this tea of the month club birthday gift and it really, really angered you. >> it wasn't about the fact that it was tea. tea is lovely. i don't happen to drink it. it wasn't the gift that upset me. he could've shown up at my doorstep and given me a hug and said happy birthday. and i would've been the happiest so glad to be with you. >> but dixon says they kept going to dinner and texting and even claims they were planning a weekend getaway. >> she was like, "hey, do you want to put this back together?" 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 my dance partner." >> okay. >> i looked her and i was like, "really?" >> 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. >> after richelle ended the relationship with dr. dixon, he started dating a medical student who was a couple of decades his junior. >> ashley woolbert is his alibi for the night of the murder. they were out eating sushi in amarillo. >> dr. dixon's sushi alibi checks out. and rochelle's alibi and sonnier's ex-girlfriends, so detective johnson is kind of starting from scratch again. >> there's somethin' not right here." but that's all that i have. we're still lookin' for a motive. this is a huge whodunit. >> but then a phone call changes all of that. it's from a total stranger who doesn't know sonnier, doesn't know richelle, doesn't know dixon, but says he may know one thing:

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don't let uc stop you from doing you. if you're living with moderate to severe ulcerative colitis, ask your doctor about once-daily zeposia. >> so at this point, this investigation is essentially at a dead end. there's no eyewitnesses, everybody's alibis check out, and at this point he has no suspects. sometimes in a murder

investigation, all you need is one tip. >> 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 to some folks. and we -- we think we've got a crime that happened down here in lubbock. it's a homicide. >> believe it or not, there are good people in the world. and paul reynolds is one of 'em. >> he's a registered nurse, a little down on his luck, and his childhood friend dave shepard is helping him out. >> so, i crashed on his couch. he kinda started with in just weird talk. >> he says shepard is spinning some wild stories about killing a man in lubbock. now reynolds is pretty sure he is making it up, but then he googles murders in lubbock and the murder is real. >> he said he went down there, and he said he shot the guy. >> what is your roommate's name? >> his name is dave shepard, s-h-e-p-a-r-d. >> shepard is unemployed.

he's divorced, and he has a criminal record. he's a convicted thief, so they bring him in for questioning. >> what do you want me to call you? dave, david? >> that'd be fine, sir. >> and guess who shepard is friends with? dr. mike dixon, richelle's previous boyfriend. shepard and dixon met over cigars and martinis at some hangouts in amarillo, bonding as they talk about their exes. >> smoking cigars is a very sociable thing. and we just connected and hooked up. >> so, you all just happened to meet up in the cigar shop, just... >> that's it. and kinda had a connection. >> shepard's daughters, hailey, abigail, and rachel know all about his friend mike dixon because their dad just seems to idolize him. >> dad was definitely obsessed with mike. like... >> really? >> he had a big man crush on mike. >> so what did you dad see in him? >> his money, and his success. >> dad wanted to be mike. >> shepard sees that dixon is obsessed with getting back with richelle shetina. >> i don't think there's

any doubt about that based on the evidence. and i think because of -- of that obsession -- he either wanted her to suffer or he wanted her back. >> he left his wife for her, you know, that she broke up his marriage. and he just wanted, i guess, payback. >> david shepard does come in and tells us exactly what happened. this whole thing was like this stair step. and it started at the very bottom of these stairs as being a prank. >> what were some of the things they came up with? >> they were gonna get this porn subscription. like, child, gay porn. and they were gonna send it to dr. sonnier's office. >> go to an adult bookstore and buy the most obscene, nastiest, man-boy love association book you could and buy him a subscription and send it to his office. because i said, "that's a gift that'll keep givin'." >> they were thinkin' that was gonna ruin his reputation, his professional reputation.

>> he pretty much wanted to break up dr. sonnier and richelle. >> ridiculous schemes to humiliate sonnier. hiring a stripper to pretend she's sonnier's girlfriend so richelle will think he's two timing her. >> none of it works. and dixon starts talking about a different plan. one that means somebody's got to get physically close to him. >> 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." he tells me that richelle and dr. sonnier take these dance classes. and he showed me where the dance class was, where to go. and he paid for everything, paid for my gas, paid for my meals. >> shepard spends months off and on in lubbock, driving two hours each way from home and watching them, consistently texting dixon about what's going on. >> it's shepard who is lurking outside richelle's gym, shepard who's sneaking into sonnier's backyard and taking kind of an accidental selfie there in the reflection in that window. that explains what richelle and sonnier saw. >> it looked like a camera flash.

and we kind of shrugged our shoulders and said, "that was weird." >> but again, none of this is helping dig up dirt on sonnier. so dixon gets impatient and it escalates. >> was there a specific act that he was wanting done that was -- was that what y'all was discussing? >> yes. >> and what was that? >> he, he wanted him hurt. and then it gradually developed into having him killed. >> after hours of interrogation, shepard confesses, and he admits he was the shooter. he gives police a blow-by-blow account of the murder, and it is completely chilling. >> shepard's final trip to lubbock, he sneaks into the doctor's backyard again. but this time, he's armed. he's got a gun and a knife, and he hides and he waits. sonnier comes home, makes himself a drink, and suddenly shepard is at the back windogun.

point the weapon with the bottle at him. discharge it several times. after three or four discharges, he's backing away. he trips on his feet. >> but the doctor doesn't fall. he stumbles out of the room. shepard runs after him. they're in the garage and that's when 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. >> there's so much blood, it seeps under the garage door to the outside. so done deal. detectives have their man. >> he's a murderer. he's a liar. he's a thief. he's an embezzler. he's lots of things. as far as his role in this, i think he was a pawn -- for mike dixon. >> they even have his dna on the gatorade bottle, which means he actually drank the gatorade before using the bottle as a silencer. >> he's confessed. he's going down.

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e of theurr trials this town has ev seen

kicks off. nobody knows they're about to start a legal saga that will last almost a decade. >> one doctor's dead and two people are under arrest. >> dr. sonnier was found shot and stabbed to death in his living room. >> this prominent plastic surgeon... >> dr. michael dixon. >> accused of hiring a hit man. >> friend and business partner david shepard. >> dave shepard has pled guilty to the murder. >> anything to say, dr. dixon? >> and says mike dixon hired him to kill dr. joseph sonnier. dallas sonnier is hellbent on bringing his father's killers to justice. >> it makes me so angry. a lowlife scum and a piece of [bleep] doctor. >> let's go [bleep] get these guys. >> there's another son in the courtroom, the son of the accused murderer. and he says "my dad, hire a murderer? no >> he did dad things. camp an end i play baseball and

football. all those things, golf. he was a good dad. he still is a good dad. they're tryin' to prove him guilty. and he's fighting for his life. i mean, it's just terrifying and so sickening. >> the gallery was packed. everybody was there to see how this trial was going to go. >> there to put andrew dixon's father way, district attorney matt powell. >> i think mike dixon had an obsession with richelle shetina. i don't think there's any doubt about that based on the evidence. ultimately that cost dr. sonnier his life. i think david shepard was the perfect patsy for this situation. i think he loved the lifestyle that dr. dixon could give him. i think he likes the expensive cigars and expensive scotch and everything else that came with being a buddy of mike dixon. >> many people make the argument that mike dixon never laid a hand on dr. sonnier. >> he's just controlling the knife. dave shepard's just another instrument for mike dixon. >> he either wanted her to suffer or he wanted her back. and only he knows what the true answer to that question is.

but dr. sonnier was in the way. this is the oldest story in the book. this is vengeance. this is revenge. this is pride. >> so what does the prosecution have? they have the gun shepard used. they found it in a lake right behind dixon's office, and it was actually registered to dixon's brother. they also have the text messages between dixon and shepard, which say the following, quote "you have to stay close. watch them in the a.m. go get 'em and put it on 'em." >> when he was arrested, the swat guys told me he had actually jumped into a swimming pool and tried to ruin the phone. the problem was the man had plugged the phone in and backed it up to his computer. so all of the stuff that he thought was not going to get him in trouble was backed up to his computer. >> and of course, the centerpiece, they have shepard's very clear confession, where he says dixon paid him to do it,

paid him with a box of cuban cigars and three silver bars. it comes to about thousand dollars. they find the bars at this pawn shop in amarillo. one bar sold here before the murder, two the day after it happens. both sold by dave sheppard. >> in terms of demeanor, he didn't strike you in one way or another it sounds like? >> no, not at all. >> a couple days later, he is on the front page of the paper. >> i was just blown away. >> dixon's lawyers say it's all very well, and it's also all very circumstantial. they have an explanation for the gun shepard uses. shepard stole it when he was at dixon's house. >> they came in here and they're picking out 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. >> the defense said that the surveilling that david shepard was doing was really only to get pictures of dr. sonnier out with other women so that he could show them to richelle and say, this guy is cheating on you.

>> richelle was posting on facebook all the time how dr. sonnier was ten times the man that mike dixon would ever be. and he wanted to show richelle that she was wrong. >> so from your perspective, it wasn't about richelle shetina, it was about mike dixon and his 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. so was i flaunting anything? no. >> and the silver bars? the defense says dixon wasn't paying for a hit. it was for an investment they had together in an allergy testing business. >> so essentially, the defense boils down to this. dixon did not ask or pay shepard to do this. shepard went rogue and did this on his own. >> 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. >> he wanted him hurt. and then, it gradually developed into having him killed. i asked him, "you sure you wanna do this, mike?" i said, "if you were -- when you kill somebody, that'll affect you for the rest of your life. you'll have nightmares. it'll bother you." and he goes, "doesn't bother me." >> shepard's daughters -- rachel, abigail, and haley -- are in court but not to support their dad. >> we were there more in support of the sonnier family. >> right. >> our heart was broken for them. >> and do you think that mike dixon paid your father to kill dr. sonnier? >> yes. >> it seemed like a slam dunk for prosecutors. they had the man who admitted to killing dr. joseph sonnier as a witness. >> and now it's time for the big moment. shepard, the man who fired the gun, is going to take the stand.

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>> every jury trial will hinge on one particular moment. the only problem is sometimes it's a moment that the prosecution does not expect. and boy, does that happen in this case. and it happens with the star witness. >> the man whose lengthy confession, the confession that says that mike dixon ordered a hit, remember? >> i said, "well, just go behind him when he's not payin' attention and hit him with a board." i said, "you could probably kill him."

and doc went like that. >> on the stand, shepard does a complete 180. 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. >> shepard says he acted alone. he completely blindsides the prosecutor, and the air is just sucked out of the room. >> in that moment, i've never hated anyone more than i've hated him in my entire life. >> david sheppard's daughters were embarrassed, angry, in incredulous their father would not finger dr. dixon as the man who hired him. >> 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. >> they went to the prison to confront him about it.

>> 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, dad. you said, "i plead the fifth. i'm not going to answer that." no part of this is right. none of it will ever be right. >> there's nothing i could do. >> no matter what you do. >> they think i'm some kind of a monster. >> you've made yourself a monster, dad! >> i mean, and 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. >> when the police interrogated you, you said mike dixon was a part of that. why did you tell them that? >> i am belus. i had agreement with mr. matt powell, the d.a., to get rid of the death penalty. >> so you made up the story that

mike dixon was involved. >> yeah. >> your daughters told us the results of this was your chance to go up there and tell the truth and in your truck with her mind you live. how does that make you feel? >> pretty bad. they should know when i am telling the truth i am not. i was telling the truth on the stand. >> do you miss them? >> every day. i'm sorry. >> this is pretty much the worst nightmare of any prosecutor. they have built their case around this confession, and it fell apart on the stand when shepard testified. so when they go back to deliberate, the jury deadlocks, the court declares a mistrial, and there is no verdict. >> the judge says, "mr. dixon, you are free to go." everybody is stunned. stunned. >> it was devastating. i mean, i had a moment of just silence.

i couldn't breathe. i couldn't think. >> but when you have a mistrial, it's important to remember, that doesn't mean the case is over. the prosecution can still bring a case with another jury. and two years later, that is exactly what they do. >> amarillo doctor michael dixon is back on trial. >> so now we have a brand-new trial and a brand new jury. but this time they've learned their lesson, and they're not going to call shepard as a witness. >> this time shepard's own daughter will take the stand. >> what did you say well flip the way you clean'em with dawn platinum ez-squeeze. it's an upside-down bottle with no cap.

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>> amarillo dr. michael dixon is back on trial for capital murder. >> back in a lubbock courtroom preparing for his second trial. >> well, today officials announce the start of the second trial. >> a retrial is a nightmare. as a prosecutor. you know you are going to hear the defense lawyer pick through every single inconsistency from what somebody said in a trial from two years before. and there's an analogy that prosecutors use. it's like putting on a cold, wet, bathing suit. >> this time they decide to have haley shepard, the hitman's daughter, testify. and the case will rest on one steak dinner her father, dave shepard, was treating his three daughters to. >> dad had money out of the blue. he just randomly had money,

and he didn't ever have money. he bought haley a phone. he bought a new grill. he bought tires. and he never had that much money ever. >> we all asked him, "how do you have money?" and his words were, "i did some work for mike, and he paid me early." >> david shepard says to her, "i did some work for mike. he paid me early. don't ask what i did for him." >> and you think that was a prepayment for killing dr. sonnier? >> in retrospect, absolutely. >> game over. >> in this trial, dr. mike dixon wants to take the stand in his own defense. and that is always a risky move. it's not just what a criminal defendant says, but how he says it and whether or not the jurors connect with him. >> the jurors later say that dixon sealed his own fate. >> i thought he was his worstes. >> i'll the lonr wthe harder s to believe. >> he had an ego that was

larger than life. and anytime he starts talking about whether something is morally right or wrong, you know, i knew at that point i could not believe what he was testifying to. >> it takes that second jury only three hours. >> and my hand was shaking like this. because i knew we'd got a guilty verdict. i knew it. i knew it. i knew it. >> the verdict is in. >> unanimous verdict. >> guilty on two charges. >> what was your first reaction? >> i had to turn to my wife and i had to say, "he -- he said guilty, right? he said guilty?" we've been waiting for that moment for over three years. >> i cried. i cried. i burst into tears. i was so relieved. >> two counts of capital murder. dr. mark dixon goes to prison. life without parole.

>> when lk at the photos of him, smug smile. when you look at his mugshot 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 finally wiped that smile off his face. >> but case closed? not even close. >> you know how when there's a guilty verdict, the defendant's lawyer always comes out to the cameras and says that they're going to appeal? sometimes that appeal actually works. >> the circuit court of appeals in amarillo reversed dixon's conviction. >> he's now out of prison living in the amarillo area. >> the circuit court actually throws out the conviction, on procedural grounds in the trial, and he orders a third trial. and again, dixon is out of prison on bond, wearing an ankle bracelet, while the d.a. scrambles to undo that ruling. >> among prosecutors, if retrying a murder case

is like putting on a cold wet bathing suit, a third retrial is like putting on a sandy cold wet bathing suit. so in the case of mike dixon, they want to go another way. so there's just one more twist. >> the d.a. takes it directly to an even higher court. and as a prosecutor, i have never seen this happen before. the texas court of criminal appeal settles it and it is a bombshell. dixon's guilty verdict is reinstated and once again, once and for all, he is guilty of murder for hire. >> eight years after dr. joseph sonnier died in his own garage, justice delivered. mike dixon is sent back to prison. life sentence, no parole. and what about the woman at the center of all of this? richelle shetina? >> this whole thing is nothing but darkness and evil. there are real sociopaths and psychopaths that walk amongst us.

they're charming. they sit at the dinner table with you and your children. they're not capable of feeling love for you or empathy for anyone. when you see that, don't ignore it. get out. run as fast as you can. >> what would she say to joseph sonnier, the man she met in a ballroom, killed by her ex, killed, essentially, by jealousy, killed for revenge? >> i would tell him i loved him. and that i'll always -- i'll always love him. i would just tell him how sorry i am. >> we should point out tonight that both mike dixon and dave sheppard, the man who pulled the trigger, are a maximum security prisons in texas. as the court said, they have no

possible chance for parole. thanks for joining us here tonight and from all of us here at "20/20" and "abc news," i'm david muir

dan: the first moments migrants tried crashing -- crossing into the southern tip of texas. the first attempt at getting into the united states since the covid for days on end, waiting for tonight. now a fierce battle over what comes next. good evening. ama: with title 42 expir biden ministration asylum policies have gone into effect. in the past two hours, legal challenges have commenced. dan: in northern california, the aclu and immigrant justice groups are challenging the policy that would require asylum-seekers to obtain proper authorization if they pass through a third country on their way to the u.s.. the lawsuit claims asylum is a legal request no matter how