incredible new scenarios. visit facebook or youtube to watch your favorite scenarios and fresh content. thanks for watching. "20/20" starts right now. what the hell happened? what could have happened here? who could have done this to them? >> a murder on a man who was fighting with everything he had. >> he's got a lot of defensive moves, which means he's trying to either disarm the man or block the assault. >> it looked like something from the movies. a chair was propped up against the door, holding it shut from the outside. jim was found nude, beaten, and stabbed to death. >> it sounds like a horrifically violent and bloody crime scene.

>> isn't it ironic that you black out at the same time he's getting stabbed? >> i need a lawyer. you guys are just trying to torture me. >> the evidence pointed out that she's the one that did it. >> i know how it looks. >> if you're not familiar with what epilepsy looks like, but knowing my parents and their limitations, it's just crazy. >> i just kept waiting for that moment, there's the lover, the affair, the $2 million life insurance policy. but nothing was there. >> do you think your mother is a murderer? >> test, test, test. okay, we're hot. the tale i'm about to tell you is that of a beautiful love story that ended in tragedy.

>> reporter: bob ruff has made a career out of america's obsession with violent crime. >> during the struggle, the chair gets knocked on to its back. the bloody knife in the water of the tub, that indicates to me that the killer believes this will wash off my dna and prints. >> reporter: his popular podcast, "truth and justice," is a deep dive into the gruesome details of tragic and bloody murder scenes. this former small town fire chief now attracts an audience of a quarter million listeners. >> this really seems like a case of actual innocence. we do a crowdsourced re-investigation of cases. a quarter of a million people working together and

investigate them as one streaming unit. and we can accomplish some amazing things. >> reporter: and he gets results. >> i think without bob and the listeners, to this day we would be sitting in prison. looking at celebrating another round of holidays without his family. >> reporter: it didn't take long for bob ruff to be deluged with requests for help. >> we get on an average month, probably a couple of dozen cases pitched to us through our case submission e-mail. and if we announce that we're looking for a new case, that number can climb into the hundreds. >> reporter: out of those hundreds of e-mails, one story grabbed his attention. it was about a family shattered by one of the most bizarre crimes he'd ever heard of. >> we screened it, started gathering information, getting documents, reaching out to the d.a. within two months, we were rolling with episode one. >> reporter: it's a case of murder that, five years later,

is still highly controversial, when bob ruff starts to peel back the layers. >> jaime estuardo melgar was born on august 10th, 1960, in guatemala. when he was just 3 years old, he immigrated to the united states. jaime was known to be very intelligent and quick with a joke. and his charms weren't lost on young sandy mcculloch. >> reporter: these high school sweethearts were soon married. jim finds work as an i.t. specialist. sandy, as a nurse. and together, they join the jehovah's witnesses, an austere christian sect that demands strict rules of behavior. their daughter lizz is now in her late 20s. what was it like growing up as the only child in the melgar family? >> you know, i always had a lot of love and attention. i think i might've taken that for granted as a teenager when, you know, you go through your rebellious years. >> reporter: lizz's cousin marissa remembers looking up to them as role models when she went to visit. >> sandy and jim were just very

loving towards each other, respectful. you could just tell they always had each other's back. they were always helping each other out. i liked watching them together. >> reporter: as daughter lizz grew up, she became especially close to her mom, sandy. what was her personality like, in general? >> she's just very caring and loving and nurturing. she was also a lot of fun. she knew how to joke around, tell a good joke. you know, i just felt like she was the embodiment of a mother, just the kind of person that you would picture when you think of that word. she was just such a loving person. >> reporter: but sandy is also a very ill person, suffering through hip replacements, hypothyroidism, lupus, and epilepsy. as a kid, you knew your mom was sick. >> mm-hmm. >> reporter: did you know she had lupus and epilepsy? >> she had epilepsy before i was born. and the lupus didn't come until i was about 3. i remember that because she had to seek treatment for about six weeks. she had gone paralyzed on one side of her body.

she was in a wheelchair. she was having a really hard time. >> reporter: more and more, sandy is leaning on the support of her husband. but jim's niece marisa says he never complained. "in sickness and in health" was a vow they lived by. >> i don't think that sandy and my uncle jim ever really got distant. if anything, i think their, you know, relationship just grew stronger and stronger. >> reporter: it's a foggy night in houston in 2012. and sandra melgar is feeling pretty good on this night, so she and her husband jim decide to go out for a celebratory dinner. it's their 32nd anniversary. >> what she's told me was that they were gonna go out to dinner. they were going to their favorite mexican place that they go almost every weekend. and they stopped by a local cvs just to grab some drink mixers on their way back home. they got home. they started getting drinks ready. they got into the jacuzzi in their bathroom.

they spent a few hours in there. just this and that, chit-chat. >> suddenly, the melgars' four dogs started barking in the backyard. so jim got out of the tub to bring the pups inside. sandy continued to soak. the jets roaring, as the water massaged her for about 5 to 15 minutes. >> i think he took a few minutes, so she decided to get out of the jacuzzi. she went to her closet, sat on her chair that she has in her closet, and started putting lotion on. >> reporter: that's the last thing that sandy says she remembers that night. the next afternoon is a planned family get-together. jim's brother herman and his family show up at about 4:30. a little behind schedule, as usual. >> here we are, running late. and he would always make fun of us for that, "here's the melgar family, always running late." >> we knocked on the front door, and no one came to open it. all we heard was the dogs barking.

>> i was telling my dad this doesn't feel right. >> reporter: what marissa and her family are about to see will haunt them forever. >> 17 stab wounds, 14 cutting wounds, and 20 blunt force wounds. these wounds would take time to kill. >> reporter: stay with us. oral defense, daily oral health chews. because for a healthy life your dog needs a healthy mouth... more than just fresh breath. frontline oral defense prevents plaque build-up and bad breath before they start. it works two ways. it scrubs down to the gum line, then the heart shaped center coats for a whole mouth clean. and a mouth that stays clean can help a dog stay healthy. because no matter how old your dog gets she'll always be your puppy. new frontline oral defense. friends & family sale!.... take an extra 20% off! save on kid's apparel... yoand a toaster oven.ust $19.99... plus - save even more on your back-to-school purchase! plus - everyone gets kohl's cash! plus - free amazon returns now at all kohl's stores! this weekend... at kohl's.

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>> reporter: jim and sandy melgar, toasting 32 apparently happy years together. dinner out, followed by romance in the jacuzzi. but saturday night becomes sunday afternoon, and their tidy brick home in suburban houston is about to reveal a grim secret and a puzzling mystery. when no one answers the doorbell, jim's brother herman enters the house through an

overhead garage door someone had left wide open. he continues through an unlocked interior door and into the house, unlocking the front door for the others. at first there is only the yapping of the four dogs, but then, from deep in the dim house, comes a feeble reply. >> at that moment, i heard someone say, "help, help!" it was sandra's voice. i began to think the worst. >> my heart dropped. i knew something was wrong. my dad, he immediately just sprang into action. >> reporter: herman follows the cry for help through the house, to the master bedroom, into the master bath. >> sandy's cries for help were coming from inside the bathroom walk-in closet. >> reporter: podcaster bob ruff. >> the scene looked like something you would see in the movies. a chair was propped up against the door, holding it shut from the outside. he grabs the chair, moves it out from under the doorknob, and slides it to the side so he can open the door.

>> and when he opened it he saw sandy lying there, tied up. >> she was lying on the floor, with her hands tied behind her, like this. well tied. and her legs, too. >> her arms are behind her back, but her arms were like this, and the bindings were wrapped multiple times around her forearms. herman tries to untie sandy's bindings from her arms, and he can't seem to find where the knot's at. sandy tells him that there's a pair of scissors on the counter near the closet. he grabs the scissors, starts cutting her out of the bindings. >> reporter: sandy seems groggy, but she's alive and apparently unharmed. but her husband jim has suffered a far more devastating fate. >> jim was found nude and beaten and stabbed to death in the master bedroom closet which is about 30 feet away from where she was at. >> reporter: his legs are tied

with a telephone cord. a rope is loosely tied around his chest. >> he's got a lot of defensive wounds on both hands, which means he's trying to either disarm the attacker or block the assault. >> reporter: celestina rossi is a crime scene investigator who helped authorities investigate the case. in her opinion, jim and his assailant were locked in hand-to-hand mortal combat right here in his bedroom closet. >> it's my opinion that the assault, and his death, occurred in the closet. >> reporter: aside from the 31 cuts and stabs, jim was badly beaten in the face and head, causing serious damage to his skull, brain, and facial bones. >> reporter: it just sounds like a horrifically violent and bloody crime scene. >> this was an ugly murder. this is a murder on a man that was fighting with everything he had, fighting for his life. he's grabbing ahold of the killer's wrists, he's hitting them. jim is blocking them, and

grabbing them, and he's stopping them from ever getting a full penetration into him. and again, all of these injuries, none of them are immediately incapacitating, so this just dragged on and on. >> reporter: when sandy is freed from the closet and sees jim's body, the family says she becomes hysterical. >> sandy was very upset. she was crying uncontrollably. but my mom was holding her back. >> reporter: there is one question hanging over the crime scene. >> what the hell happened? i'm sorry, i don't know if this is supposed to say that, but that's what i was thinking. i was thinking "what, what could have happened here? i don't -- who could have done this to them?" >> reporter: detectives and crime scene investigators swarm all over the melgar home, taking photos and video, trying to answer that question, who could have done this? floating in that jacuzzi tub where sandy says she and jim spent some of the last moments of his life, a ghostly article of clothing -- a white blouse.

also glinting in the bath water, very much out of place, a kitchen knife, which authorities believe was used to inflict many of jim's wounds. how to explain this horrifying mayhem? was it burglars, a home invasion? sure looks like it. drawers pulled out, jewelry boxes rifled, the contents of jim's wallet and sandy's purse dumped on the bed. and in the closet where jim's body was found, two items of special interest, a locked safe, and hidden on a shelf behind hanging clothes, jim's loaded gun. >> there was a loaded gun in the closet where he was found. it was located where he was found, directly above his head. you can see bloody transfer marks, like from a bloody hand where he had grabbed the closet rod, the shelf in the shirt sleeve that was right there in front of the gun. he just never, sadly, never quite got to it. >> reporter: podcaster bob ruff says those items could indicate robbers were trying to get jim

to open the safe, or that he was fighting to reach his gun to fend them off. >> jim melgar, as is the expression in texas, went out with his boots on. he did not go down without a fight. >> reporter: the gun, the safe, the ransacked rooms, sandy bound hand and foot, barricaded in a closet. the crime scene seems to be telling a story. but detectives want to hear what the sole witness who somehow survived the brutal attack has to say. >> sandy had survived. she could at least give him a description of the offenders who had tied her up. >> do you know what has happened today? >> my husband was murdered. >> how? >> i don't know. >> and that's where things really began to break bad for sandy melgar. >> reporter: stay with us. ancestrydna can reveal where in the world you're from. and with new features and richer stories, it can lead you on an unexpected journey... ...that brings you closer to home... it's only $59 to discover your heritage...

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>> reporter: 1,000 miles away from sandy and jim melgar's houston area home, here in the small town of bridgman, michigan, where violent crimes are ironically few and far between, most mornings you can

find true crime podcaster bob ruff pumping iron in his basement gym. but later ruff can be found giving his grey matter a workout in his studio as he and his producer, mike bussing, puzzle over the subject of their latest podcast episodes, the melgar case. >> we began this season with a story, because that's all we had. >> reporter: remember, it was on an afternoon just before christmas, 2012, that 52-year-old jim melgar was found brutally stabbed to death in the bedroom closet of his suburban houston home. >> luckily, detective carrizal must have thought they had at least had an eyewitness. sandy had survived. she could at least give him a description of the offenders who had tied her up. and that's where things really began to break bad for sandy melgar. >> reporter: just hours after her husband's body was discovered, sandy melgar finds herself face to face with two detectives. >> let's start from the morning when you woke up today. where were you at? >> today? >> yes. >> in the closet. >> reporter: during her two-hour

police interview, sandy seems dazed and distraught. in an unsteady voice, she relays what she says happened that fateful night. the anniversary celebration dinner at a mexican restaurant, and then the stop at a cvs drugstore to buy some drinks. after arriving at home, she said she and jim undressed and got into the jacuzzi. having a romantic, candlelit interlude. >> how long were y'all sitting there talking? >> i'd say about two hours. >> what were y'all talking about? >> the years we've had, about my daughter, about his job. nothing in particular. >> any disagreement? >> no, no. >> reporter: sometime after midnight, sandy tells detectives that her husband heard their dogs barking and got out of the jacuzzi to let them inside. >> it was taking a while, so i got out and got changed in my closet. i went in there and i started to

change and that's all i remember until i woke up. >> reporter: as incredible as it may seem, even though her husband was murdered just 30 feet away from her, sandy says she saw and herd nothing. and she blames her mind's blank slate on her epilepsy, saying she must have had a seizure. >> i usually can't move. i hurt all over and my head hurts. >> how often do you have seizures like that? >> i've been getting them more lately. i'm not able to drive anymore. >> how frequent? >> at least once a month, maybe. >> reporter: sandy's daughter lizz says it wasn't unusual for her mother to experience epileptic seizures. did you ever see your mother have a seizure? >> yeah, i did, several >> reporter: what does it look like? >> it's violent, and it's scary, especially if you've never seen one before. when she comes to, you help her into bed or help her off the floor, wherever she is. >> reporter: but the detectives clearly aren't buying sandy's

account of blacking out during the vicious attack. >> well, isn't it ironic that you black out that exact time when he's getting stabbed and bludgeoned? >> i don't have an answer for you. >> multiple times like that. dying. screaming for help. >> oh, my gosh. oh, my gosh. >> i don't understand that. that doesn't sound right to me. >> reporter: could you see why they thought it might be her? >> i could see that. i could definitely see that. it does, it sounds crazy if you don't know her situation or even if you're not familiar with what epilepsy looks like. but knowing my parents, knowing my mother and her limitations, it was just crazy. >> reporter: the detectives relentlessly turned the screws on sandy, pressing her on whether there was bad blood between her and her husband. >> was your husband abusive towards you? >> no. we got along fine. ask all of my friends. we got along great. >> did you stage that at your house, ma'am? >> stage it? >> yeah. did you plan this?

>> no, no, i did not. >> would you tell me if you did? >> i wouldn't even know where to start, to stage it. and how am i gonna tie myself up like that? and not even be able to get out of it? >> reporter: but after sandy refuses to immediately take a lie detector test -- >> i'm so stressed now. i can't even think straight. >> reporter: -- it appears the cops are no longer looking at her as a grieving spouse. they think she's a black widow. when you see your mother's interrogation tape, what does it make you think? >> it just makes me think that there were these two police officers who got tunnel vision as soon as they walked into the door and their sole purpose was just to find a way to bring charges on my mother. >> it's not really an interrogation. it's just trying to find out what happened. what do you know? she was the only one in the house. i don't think it was confrontational at all. >> i mean, one of the police officers is mimicking my dad

calling her for help. >> screaming after screaming after screaming. he's in pain. i need help. help me, sandra. sandra, i need help. >> i didn't hear anything. just stop already. >> i need help, sandra. i need help. help me. >> that's it. that's it. i need a lawyer. i'm not talking anymore. because you guys are just trying to torture me here. >> did you kill your husband? >> no, i didn't. >> we'll be back. >> reporter: while the interview may be over, she's far from out of the investigators' crosshairs. >> clearly, the evidence pointed out that she's the one that did it. >> reporter: coming up, did sandy melgar, a petite woman who suffers from lupus and epilepsy and walks with a cane, stab her husband to death and then walk away without a single drop of

blood on her? so are you saying that the homicide detectives and the prosecution have pinned this murder on sandy melgar simply because it was the expedient thing to do? a prosecutor tying herself in knots to prove her case. when "20/20" continues. frustrated that everyday activities cause wrinkles and there's nothing you can do about it? downy wrinkleguard is a fabric conditioner that helps protect you from wrinkles all day. pants washed with downy wrinkleguard and detergent are virtually wrinkle free. try downy wrinkleguard.

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>> reporter: sandy melgar's family says within a matter of hours, she goes from wife to widow to prime suspect in the brutal beating and stabbing of her husband. their niece, marissa campos, says the very evening the crime is discovered, it is immediately

obvious detectives are laser focused on a single suspect. no manhunt, no mystery. in their eyes, she says, jim melgar's murderer is standing right in front of them. it's sandy. >> all their questions seemed to be pointing towards her. it seemed like they just jumped straight to, "how was their relationship like?" "was he abusive?" they were pointing the finger at sandy. >> did you love your husband? >> yes, i loved my husband. >> did you want us to find the killer? >> of course. >> i don't think you do. >> reporter: those detectives interviewing sandy just can't accept that she could be oblivious as her husband is being murdered in the next room. >> you're in the house, and your husband's in the house, and your husband's dead. >> i know that. i know how it looks. but i was also tied up. >> reporter: but podcaster bob ruff says he doesn't see sandy as a solid suspect. >> i just kept waiting for that

moment of, there's the lover, there's the affair, there's the $2 million life insurance policy. and it wasn't there. >> reporter: even the authorities, it appears, might agree. at least, at first. the detectives interviewing sandy take a break to wake up a prosecutor in the middle of the night. but no charges, no handcuffs. sandy is free to go. she moves on, trying to pick up the pieces. enjoying time with her daughter and the growing family her husband jim never got to meet. a year and a half after the murder of her father, lizz learns of a major break in the case. a grand jury indictment. her mother. >> there was a warrant out for her arrest. we called the lawyer and we had her turn herself in. >> i was very surprised. i jumped out of bed. i went to go tell my parents what's happening. we were all just in shock. >> reporter: in spite of the murder charges, sandy is out on

bail for three years. when her trial finally rolls around in 2017, prosecutor colleen barnett has a challenge. proving that sandy ended decades of apparently happy marriage with that kitchen knife. barnett admits, she can't explain why sandy did it. >> in texas we don't have to prove a motive. i thought that i was going to be able to prove that she did what she did, that i wouldn't be able to prove motive. >> that raised red flags for me. this woman doesn't seem like she could be a killer, but the prosecutor says she is the killer, but we don't know why. >> reporter: barnett says a possible motive came to her in the middle of the trial. >> and it wasn't until the jehovah's witnesses testified from the defense and i learned a little bit about the religion that i thought possibly that might have been part of it. >> reporter: defense witnesses say the melgars appeared to have had a good marriage. nevertheless, barnett conjures a theory.

sandy wants a divorce, but afraid of being shunned by her fellow jehovah's witnesses, decides the easier option is murder. >> i don't know what her motive was. sometimes people kill people for reasons that are unknown. i'll never know why sandra killed her husband. all i know is that she did kill him. >> reporter: but if the why in this case is a head-scratcher, wait till you hear the how. barnett argues in court that sandy lured jim into letting her tie his legs with telephone cord, perhaps as some sort of sex game. >> then, all of a sudden, she pulls out a large kitchen knife and starts stabbing him. i mean, just think about what his response would be. total surprise. he's just trying to defend himself. and she keeps coming, and she's stabbing him. she stabbed him multiple times. i think, probably, he just backed up into the closet as opposed to trying to hurt her, because that was his wife. eporte ar l that evence o happened. the ransacking looks staged, she says.

drawers still neatly arranged, not dumped. >> nothing was taken out of the drawers. one of the drawers that was open had a camera in it. they had bicycles. there were prescription drugs. there were electronic devices that were there. it was a treasure trove of things to be stolen. and nothing was taken that liz could account for. >> reporter: sandy's defense attorneys, mac secrest and his niece allison, say there are things missing from the house. and that ransacking doesn't always look like a hollywood movie. >> they tried to leave the impression with the jury that for it to be a home invasion/robbery, then you have to come in and you have to literally destroy everything. and if there's an open drawer, you got to pull it out, you got to turn it upside down, throw it on the ground. >> reporter: then there's the question of blood. everyone agrees the killer probably would have been bloodied in the death struggle with jim. but sandy's hands are clean. and there's no sign anyone washed up in the house. >> if i'm the killer, i got to wash myself off.

where do i do that? when you go into the bathrooms and the bathtubs, his blood is not there. so if she's the killer, where is his blood? >> reporter: sandy's attorneys also point out the lack of injuries on her hands. >> she has fingernails. none of them are broken. none of them are chipped. so how do you hold a knife and repeatedly thrust it and hit somebody. but she never has any injury in any way to her hand. you know, she's not bruce lee or something. >> reporter: no blood spread around the house, but there was dna that doesn't match the melgar family. >> there's unknown male dna on really key pieces of evidence in this house. there's unknown female dna as well. found on the dresser drawer pulls and on door handles and on bathroom door handles. which again corroborates the fact that there was other people in this house who did this. >> reporter: sandy's attorneys tell the jury she, too, is a victim. knocked out by home invaders or

blacked out with one of her epileptic seizures. but the prosecutor shoots holes in the seizure defense. >> i got the records from her physician. every single entry that the doctor asks her, have you had a seizure? she says, no. >> reporter: from the beginning authorities have questioned sandy's account of being tied up and locked in a closet. relying on a series of houdini-style demonstrations. the very night the crime scene is discovered, officers are already re-enacting for their crime scene camera how they say sandy could have used a small rug or pillow sham to slide the chair into place under the door knob, locking herself into the closet. watch again. rug, chair, slide, presto. cops say, an air-tight, walk-in alibi. but wait, there's more. >> then i thought, okay, she's tied herself up with her hands behind her back and her feet. that sounds kind of hard to do.

so when i looked at the evidence and saw the tie that she actually used, i was able to replicate that. and i saw how easy it is to tie yourself up and make it look legitimate, though it's not. >> reporter: as she did for the jury in open court, prosecutor colleen barnett shows us how she believes sandy tied her own hands behind her back. >> it's not whether it's a legitimate tie, it's whether it looks like a legitimate tie. >> reporter: has the prosecutor given the jury enough rope to hang sandy melgar? her attorneys say no way. >> this idea that something must have happened, and then she went crazy and subjected him to over 50 blunt force and sharp force injuries is just impossible. >> reporter: still ahead, why they claim sloppy police work left clues overlooked. >> there was audible laughter in the courtroom about how shoddy this investigation was. >> reporter: and potential suspects unquestioned. >> there were people thinking, "that's as good as you're going to get?"

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>> reporter: five years after jim melgar was found fatally stabbed in his bedroom closet, his wife sandy is put on trial for his murder. after 11 days of testimony, sandy's case is sent to the jury. its foreman is tom bush. >> we all talked about how this case was the last thing you thought about when you went to bed at night, and the first thing you thought about when you woke up in the morning. that's the gravity that we weighed this case with. >> reporter: at first, bush says the jury is split down the middle. >> the scenario espoused by the prosecutor was extremely effective and, frankly, i think, really, the only viable scenario when you look at it. it was definitely a crime of passion. >> reporter: and by day two, the jury reaches a verdict. >> all of us we were all just quiet, holding hands.

just hoping for a good outcome. >> we the jury find the defendant, sandra jean melgar, guilty of murder, as charged in the indictment. it's signed, the foreman of the grand jury. >> reporter: when you heard that word read in court, guilty. >> you know, i felt like everything just got really quiet. the room was just kind of spinning. yeah, i still feel sick to my stomach when i think about it, or hear other people talk about it. >> the whole courtroom just burst into tears. there were people sobbing uncontrollably. i just couldn't believe it. i remember clearly just looking at the jurors. just staring at them, and i wanted them to look at us and just kind of so they can see what -- you know, the pain that they were causing. >> reporter: brian rogers of the "houston chronicle" was at the trial nearly every day.

>> their reaction didn't surprise me, because i was surprised, too. it didn't come back the way i thought it would come back. >> i think it's difficult to know someone for 30 years and have an idea about them, and the relationship they have. i didn't know sandra, and i didn't know the family, i could look at it with an open idea, an open mind about what had happened, and that's what i did. >> reporter: despite the verdict, sandy's family and even jim melgar's family are convinced she's innocent. for help, a family member reaches out to bob ruff. what is so outrageous about this story to you? >> i saw that the prosecution's case didn't have any meat to it. there were no bones behind why they convicted her. can i see a scenario where this happened? can i make this make sense? that sandra melgar killed her husband. in this case i couldn't see it. so we jumped in.

>> reporter: bob ruff is currently pouring through every crime scene photo. >> the chair has to be down on the ground with the blood dropping onto it that way. >> reporter: every page of testimony, no detail is too small. he believes there are a few ways an intruder could have entered the house that night, through the open garage door or through the back door, even though it was locked when police arrived. >> let's remember back to sandy's police interview. she couldn't confirm that the back door was actually locked. she never used it that day, but jim had been in and out. the offenders could have entered through the door, causing the dogs to bark. jim emerged from the master suite to check on the dogs. jim locks the door behind him, and turns around the see someone confronting him with some kind of weapon. >> reporter: and the bloody chair in the master bedroom? the prosecution says sandy moved it there to tie her husband up, and slash him to death. >> one of the things that the defense cannot answer is, what is the dining room chair doing in the bedroom, and especially where it is?

>> so the prosecution made a case that sandy lures jim into this chair outside the closet, and then is going to give him a massage, and takes a knife, and starts the attack right there. and then she drives this point home by saying there's no reason for that dining room chair to be there. it doesn't make sense that there's a dining room chair in the bedroom. but it does make sense. the crime scene photos show us this evidence. see that mark right there? >> reporter: yup. >> that's a carpet mark from that chair where it's normally kept right there. >> indicating that the chair has been there before and for some time. >> right, so they kept the chair there for the pomeranian to get on the bed. it was always kept in that location, there's no mystery there. >> reporter: at the trial, the jury saw a demonstration of how sandy could have tied herself up. but there's only one man who saw her bindings. jim's brother, who found her. he says it wasn't sandy's wrists that were bound together, but her upper forearms tied behind her back. >> her arms were behind her back in a way that nobody, especially

with her ailments -- >> reporter: you would have to be harry houdini. >> right. >> reporter: the evidence, according to the prosecution, shows that the break-in at the melgar home is all an elaborate ruse. >> the house was not ransacked. there was nothing taken. there was a treasure trove of stuff in the house that could have been stolen. none of it was stolen. none of that added up, in my mind, to a burglary. >> reporter: lizz melgar testified in court that things were stolen, and bob says the crime scene photos support that. >> to begin with, there's a lot of evidence there were, in fact, items that were stolen from the house. just to name a few, in the master bedroom, we have a nightstand with an antenna with a cable running to it, but no tv to connect to it. on the other side of the nightstand, you see another cord looks like an "s"-video cord not connected to anything. the stand's empty. neither of those two things are documented in the report. >> reporter: so if not sandra melgar, than who? at trial, the defense claimed that other potential suspects

were all but ignored. >> there was one individual who lived a few blocks away, who had been convicted of other crimes in the past, and had gotten out of jail just a few nights prior. police looked into him, they never did establish contact with him, apparently. they went to his house, he wasn't home, they left a card or something. >> there was audible laughter in the courtroom about how shoddy this investigation was. there were people thinking, "that's as good as you're going to get? you have what may be the best lead ever on somebody who could have actually done a home invasion in this neighborhood, and you left a business card?" >> the guy that lived down the street, the only evidence we had against him was that he had gotten out of jail, and was standing at the corner looking at the house along with the other neighbors. that's the only case we had against him. that's not sufficient evidence that he was the guy. >> reporter: bob believes the authorities only pursued evidence that would lead to sandy's guilt. >> the investigators were locked in to their theory. rather than letting the evidence drive the theory from moment

one, they let the theory drive the evidence. >> reporter: colleen barnett insists the investigation followed all viable suspects and leads. in the end, sandy melgar was sentenced to 27 years in state prison. the question now is, can bob's re-investigation do anything to change the ending of her story? what do you think he's found? >> i think he's found a lot of evidence that points away from her. a migfrom aimovig. to be there for the good... and not so good. for the mundane. the awe-inspiring. the heart-racing.

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>> how are you doing? >> i'm good. how are you? >> reporter: on this day in los angeles, for the first time, true crime podcaster bob ruff is meeting lizz melgar, daughter of convicted murderer sandy melgar. >> i'm really thankful for all the work that you and your listeners have put into this. i feel like we're actually moving forward. >> what you just said probably seems obvious to a lot of people. >> reporter: lizz is hoping that ruff's novel approach of crowdsourcing his podcast investigations with his audience will help get her mom out of prison. >> marissa from seattle. >> darlene wants to know, is it confirmed that items were missing from the home? >> our concept is 100,000 ordinary people from around the world have such a wide variety of skill sets that we can accomplish anything that may be some very highly paid experts can't.

>> it's something that is an absolute game changer for the innocence world. we're just beginning to see how powerful it can be. >> reporter: ruff and his avid army of listeners leave no potential clue unexamined, even honing in on the brand of that blouse found at the bottom of the jacuzzi alongside the murder weapon. >> one of our listeners zooms in on the tag of the shirt, figures out that designer made that specific shirt exclusively for costco, which is huge. because costco happens to be one of the only places where you have to have a membership card for any item that you purchase. >> reporter: so not only would it tell you whether or not sandy melgar bought it, but it might also tell you who did buy it. therefore, who might have discarded their shirt into that tub. >> exactly right. >> reporter: prosecutor barnett dismisses this kind of amateur sleuthing as irrelevant. she points out that all of the evidence was presented to a

jury, which ultimately found that sandy melgar murdered her husband. >> it's unusual, for sure, that we have a suspect that's like sandra. but that doesn't determine whether somebody commits a crime or not. >> reporter: but as far as lizz melgar is concerned, her father's killer is still out there. do you tell your kids about their grandfather? >> yeah. he would've loved them very much. it's just such a shame that he couldn't be here. >> reporter: bob ruff is determined to follow the trail wherever it leads. >> he's put in a lot of time and a lot of hard work. just really appreciative for everything he's done. because he's he's given us new hope. >> reporter: how far do you think he'll go? >> oh, he'll go all the way. he'll keep going until there's nothing else to look at. i know that she did not do this. i'm gonna continue to fight until we can prove that. >> as for now, i'm signing off. i'm bob ruff and this has been

"truth and justice." >> we should mention, the podcast has raised $20,000 for a reward to help find who he believes is the real killer. >> i'm amy robach. >> and i'm david muir. for all of us at abc news, good night. the video of an attack you saw

but for some rope a san francisco judge did not. >> the her reaction now