>> you found her. >> i did. >> detectives ruled it a suicide, but was it? >> at the scene knives, rose, a cryptic phrase. >> her hands were tied, she was naked. >> this was sending a message. >> that wasn't the only suspicious death here. >> no mom wants to hear that her son was a victim of a homicide. something happened at the top of the stairs. >> what really went on in that mansion. hear from the man at the center in his first television interview. >> you thought you had nothing to hide? >> i knew i had nothing to hide. >> the worst shock in probably my entire life. >> some places feel secluded, secure. >> i can remember saying that and feeling that, saying nothing bad could ever happen here. >> here is coronado, california. just over a bridge from san diego. a town of beautiful beaches, people and homes. like this one, on ocean boulevard. except that in the summer of 2011, this mansion became ground zero for a mystery. >> this is a very bizarre death. there is no doubt about it. >> well actually there's been plenty of doubt and plenty of theories. >> my sister was dead. and did a lot of things go through my mind? yes. >> secrets both suspected and imagined. >> is it possible that other people know more than they're saying? yes. >> it's certainly possible. beyond that it's hard to say for sure. especially when it seems everyone has a story to tell. and those stories lead to accusations, often with zero proof. >> people are gonna believe what they wanna believe with no evidence. >> paradise valley arizona was home for the shacknai family, but the summers they spent in coronado were special, for dina and her son max. >> max loves the beach, he loved the water. he used to tell me on the way to coronado, mommy this is my place. >> she and maxes father jonah met in 1997. >> we had an instant connection, it's very rare to meet someone like that. >> they married in 2001, a second marriage for jonah who was already the father of two. he'd gotten rich owning a pharmaceutical company. she went back to school to get a ph. d. in developmental psychology. and then along came max? >> and then along came maxie. >> he's almost told the edge. oh my god. he did it. how do you feel max shacknai? >> he was an active kid who loved sports and performing, for his mother and for her camera. >> mom. >> during one of those summers in coronado, a mansion on ocean boulevard was on the market. >> i said let's go by and look. >> they bought it in 2007. but soon there was trouble in paradise, and a bitter divorce in 2009 when max was four. they shared custody and worked to be civil, and it wasn't long before jonah met someone new. >> max told me about it and i said, maybe i should meet her and he said that would be great, mommy. >> rebecca zahau was 32 and born in myanmar she'd moved in the u. s. in her twenties. >> you are okay with her spending time with max? >> mack said he had feelings for her, he liked her. at that time i had no concerns because i trusted that jonah, based on our history, max would be safe there. >> and safe in coronado, were nothing bad is supposed to happen. >> tell the operator what is going on. >> hello -- >> july 11th 2011, max was staying with his dad and rebecca. dina ws in conorado too, at a home down the street that is when john a culture. >> he said dino you have to get here right away. >> as rebecca explained it to police jonah had been at the gym, six-year-old max was home with her. rebecca said she heard a crash and found max on the floor near the staircase, the mansion's heavy chandelier had fallen to the floor next to him. rebecca said max was in breathing, she started cpr. rebecca's 13-year-old sister xena who was visiting called 9-1-1. >> my sister is trying to resuscitate a boy. >> i'm sorry she -- >> he can't breathe. >> police and paramedics arrived within minutes, jonah called dina from the hospital. >> when he tells me, thank god that she was able to give him cpr i think to myself thank you, thank god. >> he's gonna be okay? >> he's gonna be okay. >> max was on conscious. dina and jonah took up a vigil at the hospital. jonah's brother adam flew in from his home in tennessee. >> you came out to support jonah? >> correct. >> how well did you know max? >> i knew max well. he was a really wonderful kid. >> at max's bedside, jonah asked one of the doctors for his prognosis. >> what was the story we're hearing about next. >> i don't think so, but that really wasn't the focus when i got there. >> it was about him getting better? >> right. >> at maxes bedside, jonah x one of the doctors for his prognosis. >> dr. peterson looked and said, i don't know. i'm not sure if he's going to walk or talk. >> that sounds like the worst news you can get? >> but it wasn't real. i would've bet my life on it at that time, that max was going to be okay. >> there was more bad news on the way. >> nine one one emergency. what are you reporting? >> yeah, i got a girl hung herself in the guesthouse. >> coming up -- >> what had happened in that home? police uncovered some disturbing clues. >> they located a female on the property. the victims hands and feats were bound. >> again thierry, my heart started racing. >> who was this victim? >> okay, how old is she? >> it's about 30. >> soon, detectives would be investigating not one just one puzzling death, but to. >> it was the worst shock in probably my entire life. >> when the mansion on ocean boulevard continues. s. organic ingredients and fermentation. fermentation? yes, formulated to help your body really truly absorb the natural goodness. new chapter. wellness well done. such tree-mendous views. i'm at a moss for words. when a cough tries to steal dad's punchlines, he takes robitussin naturals powered by 100% drug-free ingredients. are you gonna leaf me hanging? soothe your cough naturally. i don't just play someone brainy on tv - i'm an actual neuroscientist. and i love the science behind neuriva plus. unlike ordinary memory supplements, neuriva plus fuels six key indicators of brain performance. more brain performance? yes, please! neuriva. think bigger. switching wireless carriers is easy with xfinity. just lean on our helpful switch squad to help you save with xfinity mobile. they can help break up with your current carrier for you and transfer your info to your new phone. giving you a fast and easy experience that can save you hundreds a year on your wireless bill. visit your nearest xfinity store and see how the switch squad can help you switch and save. it's the xfinity black friday sales event. learn how to save up to $1000 on select phones >> the early morning hours of by visitng your local xfinity store today. july 13th 2011, as family members kept a vigil by the hospital bed of six-year-old max shacknai, a breathless man called 9-1-1. >> 9-1-1 emergency. what are you reporting? >> yeah, i got a girl she hung herself. >> once again, police raced through the streets of quiet coronado island. and once again their destination was the mansion on ocean boulevard. jonah's girlfriend rebecca was staying there, jonas brother adam had spent the night in the guesthouse. >> you wake up, you walk out, tell me what you see? >> a woman hanging, at the time i didn't necessarily think to myself, oh my goodness she's bound, or whatever. but just rebecca's hanging. >> naked, bound hand and foot, rebecca zahau was hanging by the neck from the second floor balcony. >> my heart started racing. this is actually happening. >> okay. how old isshe? >> i'd say about 30. >> 30? okay. when was the last time you saw? her >> last night. >> even as he called 9-1-1, adam said he thought she was dead. but you try to do something about it? >> i tried to do something, absolutely. it never really occurred to me that someone would look at this as a crime scene or something like that. that was the furthest thing from my mind. >> so you cut her body down? >> yeah. >> and? >> started cpr. >> to no avail? >> to no avail. >> when the coroner units arrived at the scene and located a female on the property who appeared to be deceased. >> rebecca's sister, mary zahau hundreds of miles away in missouri when her husband doug came to her work to bring her the awful news. >> i remember him saying rebecca's gone. and i said, what do you mean? i just talked to her last night. >> in that phone call, rebecca told her sister about what happened to max. it was the same story she told police. >> she said she was in the bathroom and she heard a loud noise, a loud crash, and when she came out max was there on the floor and the chandelier was close to him. he was unconscious. how did she describe jonah during those days? >> that he was upset. and it broke her heart to see him upset. >> they've met when rebecca worked for an eye doctor, and jonah was a patient. >> he came in for an appointment and started talking a next thing you know they're going out? >> apparently, yes. >> you are making an expression that makes me think that you thought that was not a particularly good idea? >> i never approved of the relationship, if that's what you're asking me. >> because? >> first of all, he's almost twice her age. >> this is one of the bat choices your parents would push away from? >> yes, as an older sister i was cautious about it, the guy is, you know, a lot older than you. >> and married before? >> and married before. and just got a divorce, and he is a c o and i said he is out of your league. >> her free spirited sister fell for jonah anyway. they seemed happy, they seemed in love? >> i think my sister loved him in her way. to her she was some what in awe of him to some extent. >> mary says that while rebecca and max were close, rebecca gave the impression she didn't get along well with max's mom. and when max had his fall, mary said, rebecca worried how deena would react. >> she was upset about it and she said, deena is going to kill me. >> she said deena is gonna kill me? >> that's correct. >> rebecca seemed upset, stressed, you get any sense that she blamed himself for what had happened? >> she seemed stressed, but not inappropriately so. >> because everybody was stressed? >> everybody was stressed. and actually sympathize with her, maybe mention that, it has to be tough on you. how terrible. >> did it cross your mind that rebecca could've been involved in max's death? >> no, nobody talked about it as being a possibility. it was -- i did not even consider that a remote possibility. >> you didn't hear anybody blame rebecca, to her face or talking about her when she was in there? >> nobody, as i said, played the blame game. it's just not -- as far as i knew, where people were at. they were just focused on max. i didn't hear anybody trying to blame rebecca. >> soon, rebecca's death became national news. in large part because of details revealed by sheriff's investigators. >> the victim's hands and feet were bound, and she was completely nude. it has yet to be determined if this will become a criminal matter or will remain as a death investigation. >> in other words, did rebeca hang herself or was someone else involved? >> a neighbor reported hearing screams the night before, was that rebecca? there was a scream that somebody heard, did you hear that? >> well, my windows were closed and i did not hear scream. >> meanwhile at the hospital, dina said she was only focused on max. she kept watch by his bedside willing him to open his eyes. it was saturday july 16th, 2011, five days after max's fall. >> i notice that his eeg was just flat. and i thought that the machine was broken, and i am shaking the machine and i'm thinking, it's not working, it's malfunctioning. and then i'm saying the eeg machine is not working, it's not working. >> but it was working, six -year-old max was gone. and dina was devastated. >> i mean, it was the worst shock in probably my entire life. >> a mother in shock and in mourning. but also questioning, how exactly had max's fatal fall happened? others asked what led to rebecca's hanging? the mystery of this mansion was only getting deeper. >> coming up. the stunning evidence inside that part of the estate, ropes, knives, a curious phrase at the scene. >> there was a message painted in black paint on the door leading to the room. but to some of the most curious thing of all is the police theory of what really happened. >> this is a very unusual circumstance. >> we conducted an experiment to see if it is possible for a person to secure their hands behind their backs in the fashion we found. >> when the mansion on ocean boulevard continues. it's another day. and anything could happen. it could be the day you welcome 1,200 guests and all their devices. or it could be the day there's a cyberthreat. only comcast business' secure network solutions give you the power of sd-wan and advanced security integrated on our activecore platform so you can control your network from anywhere, anytime. it's network management redefined. every day in business is a big day. we'll keep you ready for what's next. comcast business powering possibilities. >> in july 2011, a private funeral was held for six -year-old max shacknai in arizona. just a few days later, rebecca zahau was laid to rest in missouri. back in coronado, the mansion on ocean boulevard was the focus of overflowing numbers of both questions and rumors. >> there is roughly 200 years of experience in the sheriff's homicide unit, they all agree that this is a very unusual circumstance. >> rebecca was found hanging, naked, bound hand and foot. if it was suicide, it looked like a highly unusual one. and remember, rebecca was in the house when max shacknai fell. >> right now we don't see any connection between the two incidents. >> the sheriff's department investigated for two months. coronado held its breath. then at a news conference sheriff bill gore laid out the facts as his investigators saw them. >> was max's death a homicide? >> the answer is no. it was a tragic accident. was rebecca's death a homicide? again, the answer is no, it was a suicide. >> sergeant dave said that the evidence show showed a sad tale in which one tragedy led to another. when rebecca checked her voice mail just before 1 am, sergeant said that she heard a grim message from her boyfriend, max's dad, jonah. >> that message that was left on her phone was to inform rebecca of max's grave condition and imminent death. >> did rebecca blame herself for the child's severe injuries? and then, take her own life. the sergeant showed photos from inside the bedroom where rebecca spent her final moments. there was a rope tied to the bed, the other hand had been looped around rebecca's neck. there was also two knives in the bedroom, apparently used to cut the rope. everything was swabbed for dna. >> dna profiles were only from rebecca. >> so what about rebecca's hands and feet being tied, didn't that show another person was involved? sergeant nemeth said, it did not. >> we conducted an experiment to determine if it is possible for a person to secure their hands behind their backs in the fashion we found. >> they even showed a video demonstration, and while tying ones hands in a suicide is uncommon, the medical examiner said that it is not unheard of. >> people do it, the thinking is that they bind themselves so that they won't change their mind midway through, it's unusual at first glance but it does happen. >> the location of the apparent suicide note was also uncommon. >> is there was a message painted on the door leading to the room, i'm going to show you a message, we will not be revealing with the message said. >> the investigation left some people unsatisfied. none more so than rebecca's family. >> i know in my heart she did not commit suicide. >> also unsatisfied, dina shacknai. sheriff's investigators illustrated their findings with this graphic. they said max was riding his scooter on the second floor landing, somehow fell over the railing, then hit or grabbed the chandelier and took it down with him. >> that sounds to me like max is a stuntman, bruce lee? >> why is that ridiculous, he's six years old? kids that age do crazy things, i was seven years old i'd trumped off of the roof of the garage -- >> no. i'm absolutely positive. he was a very smart six year old. he was very athletic, he was very coordinated and he was a very careful person, a thoughtful person. >> dina did not just insist that something wasn't right, she opened her checkbook and hired her own experts. including doctor judy, a respected forensic pathologist who reviewed the autopsy report and photos and who also disagreed with the official conclusion. >> max had too many injuries to be explained with a simple accidental fall. >> the doctor thought that max's injuries indicated that he had been assaulted before he fail. what's more she suspected whether the fall could happen as the sheriff's department described it. measurements showed the railing was 32 inches high, six-year-old max was only 45 inches tall. >> his center of gravity was too low. even on a razor scooter, his center of gravity is too low to go over that banister. >> it all pointed to a chilling alternate scenario. according to the doctor, someone assaulted max, and then he somehow went over the bannister. in other words, this was a homicide. >> i would much rather have them say that this is an accident and here's what. no mom wants to hear that her son was a victim of a homicide. >> and if someone killed max, the doctor's theory focused on one person. >> i think rebecca was somehow involved, but how much she was involved and to what degree, she took that to the grave. >> that alarming suspicion was only the beginning. because it wasn't just dina who was investigating. rebecca's sister mary was equally convinced rebecca would never hurt max or kill herself out of guilt. two women coping with terrible tragedies. neither willing to accept the sheriff's department's conclusions. mary was about to make some incredible accusations. and she wouldn't back down. >> could rebecca have been killed? a second autopsy magnifies the mystery. >> there are some deep bruising and internal bleeding, which couldn't be explained by the hanging. >> but could be explained by what? >> somebody knocking her down from behind and hog-tying her. there was a struggle. >> a twist was coming. >> did you have anything to do with rebecca's death? >> absolutely not. >> you thought you had nothing to hide? >> i knew i had nothing to hide. >> one-dimensional motion boulevard continues. evard continues. ♪ ♪ cases of anxiety in young adults are rising as experts warn of the effects on well-being caused by the pandemic. ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ >> the official investigation was over, the crime scene tape long gone, that said, and unofficial search for clues was just beginning. online message boards buzzed with theories from the far fetched, to the implausible. through it all, rebecca sister mary didn't buy the official finding of suicide. was she fragile, was she easily upset? was she the kind of person that would fall apart after a crisis? >> not at all, if she is very upset to where she doesn't want to deal with the situation or feel like she can't handle it, she will go work out until she can come up with a solution and then she will come back to deal with the situation. if she doesn't think she can, then she will move on. >> so when detectives said that voice mail, the one jonah sent to rebecca with the grim news about max may have caused rebecca to hang herself mary wasn't having it. >> i was not about to have my sister's name smeared and the world remember her as this crazy woman who committed her suicide, because of a phone call. >> not plausible that she could have been hugely upset and distraught and worried and blaming herself over a significant injury to a boy that was under her care? a boy she really loved and had been taken care? of >> no. she was upset about it, but she definitely would not kill herself. >> was all of this just about how rebecca would be remembered? after her death came some revelations, things even mary hadn't known about. like in 2005 in california, when rebecca didn't show up for work and just vanished, her boyfriend reported her missing to the local police department rebecca turned up a few days later, saying it was just a misunderstanding. you're persuaded that if she did sort of mysteriously disappear back then for a day or two, it was something that she willingly did and not some sign of mental fragility? >> i really don't know what happened at that time. >> now she said, she needed to know how rebecca died. she had rebecca's body exhumed, and media friendly forensic pathologists performed a second autopsy. his conclusion? homicide. >> was rebecca murdered? her family thought so. and eventually the case found its way to this man. >> it was intriguing from the beginning. >> san diego attorney keith greer. >> the doctor did identify some of the bruising and internal bruising which couldn't be explained by the hanging. >> wait one second, it couldn't be explained by the hanging but could be explained by what? >> by somebody knocking her down from behind and hog-tying her, something along those lines. a struggle. >> plus greer says the force of falling nine feet from the balcony should've caused more severe injuries to rebecca's neck. greer like the other doctor believed someone killed rebecca and then placed her body at the end of the rope. he began to develop a theory as to who. >> the writing on the door is a key to the case. >> remember the message painted on the bedroom door? sheriffs investigators declined to reveal what it said, greer eventually found out. the message scrawled in black acrylic paint read, she saved him, can you save her. greer believes the message was not written by rebecca, it was written about her. she didn't save max? >> she did save max. at the time you have to look at it in context. >> remember rebecca said she did cpr on max after he fell. so at the time those words were written, max was still alive? >> max was alive. >> and maybe because of her effort? >> it wasn't maybe because of her effort, it was exactly because of her effort, and that's why it is the key to the case. because i know, whoever committed the murder, knew that rebecca had saved max. >> it was, he said, a small circle. mostly family. >> i had an eyewitness who put dina shacknai at the scene of the murder that evening. >> dina, the grief stricken mom. could she have blamed rebecca and then sought revenge? remember, mary recalled her sister saying, dina is going to kill me. where were you when rebecca zahau died? >> i don't know when she died, but i was in the hospital all night. >> in 2013, keefe greer filed a civil wrongful death suit on behalf of the zahau family. based on his eyewitness he named dina as a defendant along with her twin sister nina. there was also third defendant, the man who called 9-1-1, jonah's brother, adam shacknai. did you have anything to do with rebecca's death? >> absolutely not. >> greer disagreed. he pointed to those knots tied around rebecca's hands and feet. >> figuring out in the first place is hard, tying them almost impossible. >> greer believed whoever tied the knot had to be an expert, possibly a sailor. and adam shacknai worked on the mississippi river as a tugboat captain. >> when he ties things off he uses a figure eight, and then closes it with a single hitch or two, guess would not's are tied on both her legs and her hands? figure eights, tied off with a single hitch or two. >> sheriffs investigators had questioned adam extensively after rebecca's death. you didn't hold anything back from investigators? >> nothing. >> you help them to the extent that you could? >> yeah, exhaustively. >> you thought you had nothing to hide? >> i knew i had nothing to hide. >> and when investigators determined there was no evidence placing adam at the scene, they cleared you? >> they did. >> did you think this was over at that point? >> yes, i did. >> it wasn't over. rebecca's sister was determined to hold someone accountable. i'm guessing that somebody said to you that filing a lawsuit, a civil lawsuit, to financers in a criminal matter is generally an extremely unsatisfying way of pursuing justice? >> that may be, but my only recourse was the lawsuit. >> soon, they would start to get answers, just not the ones they expected. >> coming up. where was dina the night of rebecca's death? >> this eyewitness was adam, he was very clear, no doubt about it. >> powerful new video evidence and the dna evidence. where was it? >> adam shacknai admits that that morning he cut rebecca down, he loosened the ropes on her wrist to check her pulse. he gave her mouth to mouth resuscitation. >> and there's no dna? >> zero. >> when the mansion on ocean boulevard continues. evard continues. gel for powerful arthritis pain relief. voltaren, the joy of movement. >> seven years after the death of her son max, dina shacknai lives alone in the arizona home she once shared with her family. how are you even standing up right today? >> max. my son. my love for him was so great. we were a perfect fit. we were lucky. i still feel lucky. >> even though he's gone? >> yeah. i told him every day, max i love you more than anything. and then the luckiest man that ever lived in this world, because i have you. he knew that very well. and i can see that today, max, i'm the luckiest mom who ever lived, because i still have you. because love doesn't disappear just because that person is not right there. >> in the years following max's death, dina continued to investigate, and hired a woman named tara schneider. you are convinced that max died not as a result of an accident but a murder? >> yes, a homicide. >> tara has no law enforcement background. she calls herself an intelligence analyst. she and dina have floated several theories over the years, the current theory, whoever killed max, it was not rebecca zahau. these days their suspission is focued on information from a neighbour that has never been verified. a story of all wild party at the mansion the night before max's fall. >> he has not been interviewed by the police and has not come forward. >> my would connection it might have to maxes death, you have no idea? >> i don't. but i think it should be explored. >> she said police never spoke with a neighbor but we did and he doesn't remember anything about a party. and max's data jonah shacknai who was in the house said that there was no party. jonas says that he never doubted the official investigation, but wanted to rebut the theory offered by tina and others. his lawyers hired the highly regarded investigative firm, crawled, the resulting report says that the evidence is consistent with an accidental, tragic fall. and there is no evidence of foul play, malice, or other not accidental ocurrents. how many people said to you, you need to let this go and move on? >> many. so many. >> even if she'd wanted to move on, it really wasn't possible, because dina, remember, was being sued by the family of rebecca zahau, who blamed dina, in part, for rebecca's death. through it all, dina stuck to her story that she'd been at max's bedside at the hospital the night rebecca died. even though the zahau attorney keith greer had a witness willing to testify that he saw dana outside the mansion that night. adamant. he was very clear, no doubt about it. >> and turned out to be dead bang wrong? >> dead wrong. >> in april 2017, after four years of litigation, this security camera video came to light. it's from the hospital where max shacknai was being treated. the same night rebecca zahau died. clearly visible dina shacknai. at some point you look at the footage and you realize, i'm wrong. and my witness is wrong. dina won their, she was at the hospital provably. >> absolutely. i got mad. i got really mad. >> greer called a press conference to publicly eat some crow. >> when these pictures come out though, you can't refute them. >> he removed dina from the lawsuit along with her sister nina. and the family attorney apologized to you, was that enough? >> he made a public apology. i would say that not as many people saw the public apology, as who saw continuous accusations against us. >> he pushed forward anyway with just one defendant adam shacknai. that's to me, this is some scattershot attempt and you are suing everybody that comes into your line of sight looking for a sympathetic jury. >> that's it. a lot of people looked at it that way. >> why shouldn't that shatter the credibility of the rest of your case? >> i think the reality of it is that we always had adam involved all through the process. >> in the lawsuit, greer outlined a detailed and substantiated narrative. he argued rebecca was killed not to avenge max, but instead during a sexual assault. greer's theory is that it began after rebecca stepped out of her shower and saw adam watching her. >> she didn't get some comfortable tries to escape, screams for help, at 11:30 that night. >> he says that explains the screams heard by a neighbor. >> right after that, to silence her adam hits her at the back of the head knocks or partially unconscious and then he thinks, wraps the black pink and paints this phrase on the door. >> she saved him, can you save her. >> if i'm gonna kill somebody and try to make it look like a suicide, i'm not gonna write a cryptic phrase behind, i'm gonna write a phrase that said i'm sorry, i'm guilty i did it. >> it wasn't staged to be a suicide. >> even greer said evidence placing adam at the scene is weak. >> adam shacknai had any marks or scrapes that there had been a struggle with anyone. >> none. >> same with adams dna. >> it's pretty hard to get rid of your dna. >> hard to get rid of dna. all right. adam shacknai admits that that morning he cut rebecca down, he loosen the ropes on her wrist to check her pulse. he gave her mouth to mouth resucitation, he gave cpr pumps to her chest -- >> and there's no dna? >> how much dna and how many fingerprints are found on the knife, the rope, her body, how much? >> none. >> zero. zero. >> zero of adams, that is. rebecca's dna and fingerprints were everywhere. according to greer, that means adam who had no criminal history knew exactly how to wipe down the scene, somehow removing his own fingerprints and dna but leaving just rebecca's. of course, it could also mean that adam simply wasn't there when rebecca died. which is exactly what law enforcement came to believe. i'm guessing that if you walk in court in any case, and imposing council says, there is no evidence here, there are no fingerprints and there's no dna, and that is the proof of the case that i am bringing, you would think to yourself, i have a grand ball here. >> the absence of evidence isn't the evidence of absence. and so, we know it's murder because it's wiped down. we know it's not suicide. >> would a jury agree? -- and blamed herself and realized that everybody else was going to bring blame her to or at least thought they would do that and took her own life as a result? >> the way it was done doesn't fit that. if there was a note that said, i'm sorry everybody. i loved their max. i was there for him. i'm sorry for all of. you >> and i feel responsible? >> it's too much for me to bear. that would be one thing. and then overdosing on ambien, which was available there. may have fit. but this was sending a message. this was stripped naked, hung up for the world, with no direct no seeing what happened. the honor theory just didn't work. it just didn't fit. >> would a jury agree? greer had to prove adam shacknai was somehow responsible for rebecca's death that his own actions made him liable. in a wrongful death civil case the standard is more likely than not. a significantly lower bar than beyond a reasonable doubt which is the standard in a criminal case. it is however still a challenge, and when the case went to trial, keith greer would be against a top notch defense team. did you feel overmatched? >> i was so a gun was pathetic. >> coming up, two families connected by tragedy, prepare to go head to head in the courtroom. >> did you attack her? >> no. >> did you sexually assault her? >> no. >> did you tie those knots on her body? >> no. >> would a jury believe him? >> i sat down next to mary, i said merry, i'm sorry, this is probably not good news. >> when the mansion on ocean boulevard continues. ulevard continues. or an intense burning sensation. what is this nightmare? it's how some people describe... shingles. a painful, blistering rash that could interrupt your life for weeks. forget social events and weekend getaways. if you've had chickenpox, the virus that causes shingles is already inside of you. if you're 50 years or older ask your doctor or pharmacist about shingles. ♪ my songs know what you did in the dark ♪ ♪ so light 'em up, up, up light 'em up, up, up ♪ ♪ light 'em up, up, up ♪ ♪ i'm on fire ♪ ♪ so light 'em up, up, up light 'em... ♪ ♪ baby got back by sir mix-a-lot ♪ ♪ i'm on fire ♪ unlimited cashback match... only from discover. (tiger) this is the dimension of imagination. ♪ ♪ the xfinity black friday sales event is happening now on xfinity mobile. now new and existing customers can get our best wireless deal of the year - up to $1,000 in savings - for a limited time only. on the most reliable network nationwide, plus nationwide 5g. act now and save up to $1,000 with xfinity mobile. so you can go all out on gifts for the family - during our best wireless deal of the year... the xfinity black friday sales event. click, call or visit a store today. >> the attorney had a lot of imagination. >> adam shacknai says it's simple, he had nothing to do with the death of rebecca zahau. were you present when she died? >> no. >> did you attack? or >> no. >> did you sexually assault? or >> no. >> did you tie those knots on her body? >> are those the kinds of knots that only a sailor or someone who worked around boats would know? >> no, those are common knots. >> the sheriff's investigator found no evidence adam was present when rebecca died, and they cleared him. that didn't stop rebecca's family from suing in civil court. the lawsuit, the long string of accusations, what do you think is going on here? >> it's denial, it's they don't wanted to be seen that their sister committed suicide. >> we asked rebecca's sister mary about that. a lot of times, families do not want to admit that someone committed suicide. because they blame themselves for not maybe having seen the signs, is that what you're doing here? >> no. and i have been accused of that multiple times, including the sheriff's department. >> is it possible that rebecca was depressed and you missed it? >> no. >> in march 2018 the wrongful death long sued began incendiary go. defending adam was dan web, former u.s. attorney and a veteran of many courtrooms. >> there is no evidence that shows that adam shacknai had anything to do with the death of rebecca zahau. >> in particular, no dna or fingerprints from adam were found at the death scene. plaintiffs attorney keith greer called several experts who testified that the lack of physical evidence could show that adam had cleaned up after himself. >> there was nothing on the doorknobs whatsoever. as far as prints. >> and that's consistent with them being wiped down? >> yes. >> and a handwriting expert who looked at that message on the door. >> the writing on the door is more consistent with adams than rebecca's. >> greer also claims that rebecca had been sexually assaulted with a knife prior to her murder. his expert testified a steak knife found in her bedroom had her blood in the handle. greer said the sheriff's department had overlooked that evidence. >> they never considered that. they never analyzed that. >> to defense called a forensic technician who does testified she did find the blood on the knife and with it a simple explanation. a recent cut on rebecca's right hand. and when greer asked her if the blood could've come from a sexual assault? >> i didn't see any evidence of that. >> no evidence. a point the defense hammered home. >> no fingerprint evidence. no finger evidence that was indentified or directed to adam shacknai. >> all the items i tested, he was excluded. >> adam's brother jonah took the stand, he called rebecca's death unfathomable, but said adam was not responsible. >> is there anything that adam has ever done in his life that would cause you to believe that he ever would've done the acts that he is accused of in this case? >> never. anything, it's inconceivable. >> adam took the stand too. >> did you hit rebecca on the head? >> i never hit her back on the head. or anywhere else, for that matter. >> did you devise this scheme to try to cover up your wrongdoing by painting the saying on the door and making it look like she had been hanged by someone else? >> absolutely, positively, not. >> the case went to the jury. >> did you feel confidence as deliberations began? >> i felt like we could possibly win very convincingly. >> less than four hours later, a verdict. >> i sat down next to mary and said, i'm sorry, this is probably not good >> the jury coming so quick, it's probably not gonna be in your favor. you didn't like -- you can let rebecca die in vein. this was it a decision that even keefe greer would be in for quite a plot twist. >> number one did adam shacknai touch rebecca-- before rebecca zahau's death with the intent to hurt? the answer is yes. did that touching cause the death of rebecca zahau the answer is yes. >> yes, meaning that the jury found adam shacknai responsible for rebecca zahau's death. >> i just broke down. i was just like ok, i'm not crazy. i'm not the only one who believes that adam murdered my sister. >> that's not quite what the jury said. finding someone liable in a civil case is not the same as finding them guilty of murder. what's more, the verdict in this case did not have to be unanimous, and it wasn't. nine jurors found adam responsible, three did not. the jury did award the zahau family $5 million. >> courtrooms are supposed to be a place where justice is dispensed, was this about justice? >> no, it wasn't. >> since this wasn't a criminal case, adam didn't go to jail, he returned home to tennessee and filed a motion for a new trial, which was denied in january 2019. then in february, adam's insurance company and rebecca's family reached a settlement of $600, 000, and the case was dismissed. after the civil trial, the sheriff's department took a fresh look at rebecca's death. eight months later, that review also concluded that rebecca died by suicide. dina shacknai would like to see authorities reinvestigate her son's case. do you think they will reinvestigate max's death? >> i think it's the right thing to do. do i think it will happen? i really don't know. >> how does a mother ever truly accept the tragic loss of her child? the ripples keep on spreading to this day. in a place where nothing bad was supposed to happen. >> i'm craig melvin. >> and i'm natalie morales. >> and this is "dateline. " >> she had missed a meeting and then not to hear from her, this isn't right. it would have been impossible to get up every day knowing that she was gone. i had to believe we would find her alive. >> text her, she always got right back. >> i've seen her step out of the shower to answer her phone. >> then one day she didn't. >> immediately my spidey senses were high. >> where was nailah? >> i sent her an e-mail, all caps, "are you alive? "