memory now. greer said the sheriff his trail of victims safe from department overlooked that his terror. evidence. thanks to a young woman and a >> that's nowhere on any of the sheriff's records. little dog who fought for her they never considered that. life -- they never analyzed that. >> reporter: the defense called and won. a forensic technician who testified she did find the blood that's all for now. thanks for joining us. on the knife. and with it, a simple explanation. >> that's all for this edition a recent cut on rebecca's right of dateline. hand. and when greer asked her if the blood could have come from a sexual assault. i'm natalie morales. >> i didn't see any evidence of thanks for watching. that. i'm craig melvin. >> reporter: no evidence. >> andcr i'm natalie morales. a point the defense hammered >> and this is dateline. home. >> i saw no fingerprint evidence that was identified or directed towards adam shacknai. >> i know my sister would have >> of all the items i tested, he was excluded on all of the fought. items. we used to tell each other that if somebody ever tried to hurt >> reporter: adam's brother jonah took the stand. us, that we would do everything he called rebecca's death we can to leave something behind so the other one can figure it "unfathomable," but said adam out. was not responsible. >> is there anything that adam's i believe she was murdered. ever done in his life that would cause you to believe that he >> this is a very bizarre death. ever would have done the acts that he's accused of in this >> it was baffling from the case? start. >> never anything. a young woman dead at her it's inconceivable. millionaire boyfriend's mansion.

>> reporter: adam took the stand >> 911 emergency, what are you reporting? too. >> yeah, i got a girl, hung >> did you hit rebecca on the herself. i >> my heart started racing. head? >> reporter: you found her hanging? >> i never hit rebecca on the >> i did. >> detectives ruled it a head. suicide. or anywhere else for that matter. but was it? >> and did you devise this at the scene -- knives. scheme to try and cover up your ropes. wrong doing by painting this a cryptic phrase. >> her hands were tied. saying on the door and making it her feet were tied. look like she had been hanged by she was naked. >> this was sending a message. someone else? >> that wasn't the only >> absolutely, positively not. suspicious death here. >> reporter: the case went to the jury. did you feel confident as >> no mom wants to hear that her deliberations began? son was the victim of a homicide.m >> i felt we could possibly win >> something happened at the top of the stairs. >> what really went on in that very convincingly. mansion? >> reporter: less than four hours later, a verdict. >> i sat down next to mary and i hear from the man at the center said, "mary, i'm sorry. in his first television this is probably not good news." interview. >> reporter: you thought you had nothing to hide. >> reporter: this was it. a decision. >> i knew i had nothing to hide. >> the worst shock in probably and even keith greer would be in my entire life. for quite a plot twist. >> number one, did adam shacknai touch rebecca zahau before rebecca zahau's death with the intent to harm her? the answer is yes. number two, did that touching cause the death of >> hello and welcome to rebecca zahau? dateline. victims families have often the answer is yes.

described their feeling of loss simply as surreal. >> reporter: yes, meaning that the jury found adam shacknai and sotist for both the responsible for rebecca zahau's families. death. their tragedies were tangled in >> i just broke down. one riveting mystery that i was just like, "okay. captivated the nation.iv at the center of the story two i'm not crazy. puzzling deaths and lingering i'm not the only one who suspicions. the search for the truth would believes that adam murdered my pit the families against each sister." other in a battle sparking more >> reporter: that's not quite questions than answers. what the jury said. here's josh mankiewicz with "the finding someone liable in a mansion on ocean boulevard." civil case is not the same as finding them guilty of murder. >> reporter: some places feel what's more, the verdict in this case did not have to be secluded. insulated.d. unanimous, and it wasn't. secure. nine jurors found adam >> i can remember saying that responsible. and feeling that and saying, in three did not. "nothing bad could ever happen the jury did award the zahau here." family five million dollars. >> reporter: "here" is coronado, courtrooms are supposed to be a california, just over a bridge place where justice is from san diego. dispensed. a town of beautiful beaches, was this about justice? people and homes. >> no, it wasn't. >> reporter: since this wasn't a like this one on ocean boulevard. criminal case, adam didn't go to jail. he returned home to tennessee. except that since the summer of

2011, this mansion has been he returned home to tennessee and filed a motion for a new ground zero for a mystery. >> this is a very bizarre death. there's no doubt about it. >> reporter: well, actually, trial. there's been plenty of doubt. then in february they reached a and plenty of theories. settlement of $600,000 and the >> my sister was dead. case was dismissed. and did a lot of thing go after the civil trial the through my mind? yes. >> reporter: secrets both sheriff's department took a suspected and imagined. fresh look at rebecca's death. >> is it possible that other eight months later that review people know more than they're saying? also concluded that rebecca died yes. >> reporter: it's certainly by suicide. possible. dina shacknai would like to see beyond that, it's hard to say for sure. authorities reinvestigate her son's case. especially when it seems do you think they will reinvestigate max's death? everyone has a story to tell. >> i think it's the right thing and those stories lead to h to do. accusations. do i think it will happen? often with zero proof.on i really don't know. >> people are going to believe what they want to believe with >> how does a mother ever truly accept the tragic loss of a no evidence. >> reporter: paradise valley, child? the ripples keep on spreading to arizona, was home for the shacknai family. this day. in a place where nothing bad was but the summers they spent in supposed to happen. coronado were special for dina and her son max. >> max loved the beach. >> that's all for this edition he loved the water. of dateline. i'm natalie m natali and he used to tell me on the d

way to coronado, "mommy, this is our place." >> reporter: she and max's dad, jonah, met in 1997. >> we had an instant connection. it's very rare you meet someone like that. to find out that she's gone. >> reporter: they married in 2001, a second marriage for jonah who was already the father and the cause is a gunshot of 2. wound. he'd gotten rich owning a pharmaceutical company called you just wonder, how could this happen? medicis. she went back to school to get a it seems very surreal. ph.d in developmental psychology. and then along came max. >> a quiet night at home >> and then along came maxie. >> he's almost to the edge.he oh, my. shattered by a gunshot. >> she came out of the shower, he did it. and i heard a pop, and there's blood! >> a young wife dying on the floor. how do you feel, max shacknai? >> reporter: he was an active kid who loved sports and performing for his mother and her camera. >> mom, this is my song, right? >> it is, yeah. >> reporter: during one of those summers in coronado, the mansion on ocean boulevard was on the market. >> and i said, "well, let's just go by and look."

>> reporter: they bought it in 2007. but soon there was trouble in paradise and a bitter divorce in 2009, when max was 4. they shared custody and worked to be civil. and it wasn't long before jonah met someone new. >> maxie, told me -- about it.on and i said, "wow, well, maybe i should meet her." and he said, "that would be great, mommy." >> reporter: rebecca zahau was 32, born in myanmar. she had moved to the u.s. in her 20s. you were okay with her spending time with max? o >> well, max 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. >> reporter: and safe in coronado, where nothing bad is supposed to happen. >> tell the operator what's going on. >> hello, um -- >> reporter: july 11th, 2011. max was staying with his dad and rebecca. dina was in coronado too, at a home just down the street. that's when jonah called her.

>> and he said, "dina, you've gotta get here right away." >> reporter: as rebecca explained it to police, jonah had been at the gym. 6-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 wasn't breathing, and she started cpr. rebecca's 13-year old sister xena, who was visiting, called 911. >> my sister's trying to resuscitate a -- a -- um, a boy. >> i'm sorry -- she? >> he can't breathe. >> reporter: police and paramedics arrived within te minutes. jonah called dina from the hospital. >> and he tells me, "thank god that she was able to give him e cpr." i think to myself, "thank -- my god." >> reporter: he's gonna be okayo >> he's -- he's gonna be okay. >> reporter: max was unconscious. 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? h

>> correct. >> reporter: how well had you known max? >> i knew max well. he was a really wonderful kid. >> reporter: at max's bedside, jonah asked one of the doctors for his prognosis. >> peterson looked at him and so said, "well, i don't know. i don't know. i'm not sure if he's gonna walk or talk." >> reporter: that sounds like te about 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 gonna be okay.e >> reporter: there was more bad news on the way.te >> 911 emergency. what are you reporting? >> yeah, uh, i got a girl -- hung herself in the guest house. >> what had happened in that house? police uncover some disturbing clues. coming up -- >> they located a female on the property. the victim's hands and feet were bound. >> i guarantee you, my heart started racing. >> who was this victim? >> okay, how old is she?

>> she's 30. >> 30, okay. when was the last time you saw her? >> y last night. >> soon detectives would be investigating notct just one puzzling death here but two >> it was the worst shock in probably my entire life. >> when dateline continues. >> when dateline continues ♪ protect your pet with the #1 name in flea and tick protection. frontline plus. trusted by vets for nearly 20 years. my job is to help new homeowners who have turned into their parents. i'm having a big lunch and then just a snack for dinner. so we're using a speakerphone in the store. is that a good idea? one of the ways i do that is to get them out of the home. you're looking for a grout brush, this is --

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as family members kept a vigil by the hospital bed of 6-year-old max shacknai, a breathless man called 911. >> 911 emergency. what are you reporting? >> yeah, uh, i got a girl -- hung herself. >> reporter: 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. jonah's brother adam had spent the night in the guest house. >> 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. >> reporter: naked, bound hand and foot, rebecca zahau was hanging by the neck from a second-floor balcony. >> i said -- i guarantee you, my

heart started racing. this is actually happening. >> okay. how old is she? >> i'd say about 30. >> 30? okay. when was the last time you saw her? >> last night. >> reporter: even as he called 911, adam says he thought she was dead. but you try to do something? >> i try to do something. absolutely. and it was not -- never even occurred to me that somebody would look at this as, like, a -- you know, a crime scene or something like that. i mean, that was the furthest thing from my mind. >> reporter: so you -- you -- you cut her body down? >> yeah. >> reporter: and? >> started cpr. >> reporter: to no avail. >> reporter: to no avail. >> when the coronado units arrived at the scene, they located a female on the property who appeared to be deceased. >> reporter: rebecca's sister mary zahau-loehner was hundreds of miles away in missouri when her husband doug came to her work to bring her the awful news. >> i remember him sayin', "rebecca's gone."

and -- and i said, "what do you mean? i just talked to her last night." >> reporter: 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 a the floor. and the chandelier was close to him, and he was unconscious. >> reporter: she describe jonah during those days? >> that he was upset and it broke her heart to see him upset. >> reporter: they'd met when rebecca worked for an eye doctor and jonah was a patient. he came in for an appointment and they started talking, and next thing you know, they're goin' out. apparently, yes. >> reporter: you are making an expression that makes me think that you thought that wasn't a particularly good idea. >> i never approved of the relationship, if that's what you're asking me. >> reporter: because? >> first of all, he is almost

twice her age. >> reporter: her free-spirited sister fell for jonah anyway. they seem happy? they seem in love? >> i think my sister loved him in her way. to her, she was somewhat in awe of him. i think to a certain extent. >> reporter: 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 dina would react. >> she was upset about it. and she said, "dina is going to kill me." >> reporter: she said, "dina's gonna kill me"? >> that's correct. >> reporter: rebecca seemed upset, stressed? you get any sense that she blamed herself for what had happened? >> she seemed stressed but not inappropriately so. >> reporter: 'cause everybody was stressed? >> everybody was stressed. and i actually sympathized with her, maybe even mentioned that, of just, "it's gotta be, you know, tough on you. how terrible." >> reporter: 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. >> reporter: in other words, did rebecca 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. you hear that? >> well, my windows were closed. i did not hear a scream. >> reporter: meanwhile, at the hospital, dina says she was only focused on max. she kept watch by his bedside, willing him to open his eyes. it was saturday, july 16th, 5 days after max's fall. >> and i noticed that his eeg was just flat. and i thought -- i thought the machine was broken. and i'm shaking the machine. and i'm thinking it's not working.

it's malfunctioning. i'm shaking. and then i'm saying, you know, "the eeg machine's not working. the eeg's not working." >> reporter: but it was working. 6-year-old max was gone. and dina was devastated. >> i mean, it was the worst shock in probably my entire life. >> reporter: 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 at this mansion was only getting deeper. >> coming up -- ropes. knives. a curious phrase at the scene. >> there was a message painted in black on the door leading to the room. >> but to some -- the most curious thing of all? the police theory of what really happened. >> this is a very unusual circumstance. >> we conducted an experiment to determine if it is possible for

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>> reporter: 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's roughly 200 years of

experience in the sheriff's homicide unit. they all agree, this is a very unusual circumstance. >> reporter: 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. >> reporter: 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. >> reporter: sgt. dave nemeth said the evidence told a sad tale, in which one tragedy led to another. when rebecca checked her

voicemail just before 1:00 a.m., sgt. nemeth said 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. >> reporter: 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 end had been looped around rebecca's neck. there were also two knives in the bedroom, apparently used to cut the rope. everything was swabbed for dna. >> dna profiles were only from rebecca. >> reporter: so what about rebecca's hands and feet being tied? didn't that show another person was involved? sgt. nemeth said it did not. >> we conducted an experiment to

determine if it is possible for a person to secure their hands behind their back in the fashion we found. >> reporter: they even showed a video demonstration. and while tying one's hands in a suicide is uncommon, the medical examiner said it's not unheard of. >> people do it, the thinking that they bind themselves so that they won't change their mind mid-way through. it's unusual at first glance, but it does happen. >> reporter: the location of the apparent suicide note, was also uncommon. >> there was a message, painted in black paint on the door leading to the room. i am going to show you a picture of the door. we will not be revealing what the message said. >> reporter: the investigation left some people unsatisfied, none more so than rebecca's family. >> i know in my heart she did not commit suicide. >> reporter: 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 is max some sort of -- you know, a stunt man, bruce lee? that's ridiculous. >> reporter: why is that ridiculous? he's six years old. kids that age do crazy things. when i was seven years old, i jumped off the roof of the garage holding an umbrella as a parachute. >> no. 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. >> reporter: dina didn't just insist something wasn't right. she opened her checkbook and hired her own experts, including dr. judy melinek, 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. >> reporter: dr. melinek thought max's injuries indicated he'd

been assaulted before he fell. what's more, she questioned whether the fall itself could have happened 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 the razor scooter, his center of gravity's too low to go over that bannister. >> reporter: it all pointed to a chilling, alternate scenario. according to dr. melinek, someone assaulted max, and then, he somehow went over the bannister. in other words, this was a homicide. >> i would much rather have them just say, "you know what? this was an accident. and here's why." no mom wants to hear that her son was a victim of a homicide. >> reporter: and if someone killed max, dr. melinek'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. >> reporter: 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. coming up -- >> some deep bruising and internal bleeding couldn't be explained by hanging. >> reporter: but could be explained by what? >> someone knocking her from behind and hog tying her, something along those lines, a struggle. >> a twist was coming. >> reporter: 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. g to hide. >> i knew i had nothing to hide. that lets you shop over 17,000 cars from home.

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here's what's happening. tropical storm isaias is set to pick up strength as it races towards south eastern florida. forecasters predict it will reach hurricane status again dumping heavy rain on the state before heading north. the state of florida is also struggling to contain the spread of coronavirus. there are nearly half a million cases of the virus, and more than 7,000 people have died from covid-19. on thursday alone more than 250 died from the virus. now back to dateline. welcome back to dateline. i'm natalie morales. police have ruled 6-year-old max shacknai's fatal fall an accident and rebecca zahau's hanging a suicide. but neither rebecca's sister nor max's mom were convinced. each suspected foul play and one of them was about to make an

explosive accusation. >> reporter: the official investigation was over. the crime scene tape and evidence markers long gone. that said, an unofficial search for clues was just beginning. online message boards buzzed with theories from the farfetched to the implausible. and cable shows like dr. drew on cnn's headline news channel were a platform for a very vocal sister mary. >> and we believe that god is going to reveal at some point what happened to my sister. official finding of suicide. >> was she fragile? was she easily upset? is she the kind of person who would fall apart after a crisis? >> not at all. >> reporter: so when detectives said that voicemail, the one jonah shacknai left for 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.

>> reporter: was all 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. >> reporter: 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 -- i really don't know what happened at that time. >> reporter: now she said she needed to know how rebecca died. with the assistance of the dr. phil show, she had rebecca's body exhumed. media-friendly forensic pathologist dr. cyril wecht then 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. >> reporter: san diego attorney keith greer. >> dr. wecht did identify some deep bruising and internal bleeding, which couldn't be explained by the hanging. >> reporter: 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. a struggle. >> reporter: plus, greer says, the force of falling nine feet from the balcony should have caused more severe injuries to rebecca's neck. greer, like dr. wecht, believed someone killed rebecca and then placed her body at the end of the rope. and he began to develop a theory as to who. >> the writing on the door is the key to the case. >> reporter: remember the message painted on the bedroom door? sheriff's investigators initially 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 believed the message was not written by rebecca, it was written about her. >> reporter: who'd she save? she didn't save max. >> she saved max. she did save max. at the time. you have to look at this in context. >> reporter: remember, rebecca said she did c-p-r on max after he fell. >> reporter: so at the time, those words were written, max was still alive. >> max was alive. >> reporter: and maybe because of her efforts. >> it wasn't maybe because of her efforts. it was exactly because of her efforts and that's why it's the key to the case because i know whoever committed the murder knew that rebecca had saved max. >> reporter: 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. >> reporter: dina, the grief stricken mom. could she have blamed rebecca and then sought revenge? remember, mary recalled her sister saying, "dina's going to

kill me." >> reporter: where were you when rebecca zahau died? >> well i don't know what times rebecca zahau died during that time, but i was at the hospital all night. >> reporter: in 2013, keith greer filed a civil wrongful death lawsuit 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 a third defendant. the man who called 9-1-1, jonah's brother, adam shacknai. >> reporter: did you have anything to do with rebecca's death? >> absolutely not. >> reporter: greer disagreed. he pointed to those knots tied around rebecca's wrists and ankles. >> figuring them out in the first place is really hard. tying them, almost impossible. >> reporter: greer believed whoever tied the knots 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 what knots are tied on both her legs and her hands? figure eights tied off with a single hitch or two. >> reporter: sheriff's investigators had questioned adam extensively after rebecca's death. >> reporter: you didn't hold anything back from investigators? >> nothing. >> reporter: you helped them to the extent that you could. >> yeah, exhaustively. >> reporter: you thought you had nothing to hide. >> i knew i had nothing to hide. >> reporter: and when investigators determined there was no evidence placing adam at the scene -- >> reporter: they cleared you. >> they did. >> reporter: did you think this was over at that point? >> yeah, i did. >> reporter: it wasn't over. rebecca's sister was determined to hold someone accountable. >> reporter: i'm guessing that somebody said to you that filing a lawsuit, a civil lawsuit, to

find answers in a criminal matter is generally an extremely unsatisfying way of pursuing justice. >> that may be, but my only recourse was the lawsuit. >> reporter: soon they would start to get answers, just not the ones they expected. >> coming up -- where does dina the night of rebecca's death? >> this witness was adamant. >> powerful new video evidence and the dna evidence. where was it? >> adam shacknai admits that that morning he cut rebecca down. he loosened the rope oz on her wrist to check her pulse. he gave her mouth-to-mouth resuscitation. >> and there's no dna. >> zero. suscitation. >> and there's no dna. >> zero. outdoor allergens. like those from buddy. because nothing should come between two best friends. feel the clarity, and live claritin clear.

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can it help keep me asleep? smart bed is on sale now. absolutely, it intelligently senses your movements and automatically adjusts to keep you both comfortable. save up to $500 on select sleep number 360 smart beds. plus no interest until january 2023 & free delivery on most beds when you add a base. ends monday >> reporter: 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 upright today? >> max, my son. my love for him was so great. >> we were a perfect fit. we were lucky. i still feel lucky. >> reporter: even though he's gone? >> yeah. >> reporter: in the years following max's death, dina continued to investigate and hired a woman named tara schneider. you're convinced that max died not as the result of an accident but a murder.

>> yes. homicide. >> reporter: 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 suspicion is focused on information from a neighbor that's never been verified. a story of a wild party at the mansion the night before max's fall. >> he has not been interviewed by the police and he has not come forward. >> reporter: but what connection it might have to max's death, you have no idea what that is. >> i don't. but i think it should be explored. >> reporter: she said police never spoke with the neighbor. but we did. and he doesn't remember anything about a party. and max's dad jonah shacknai, who was in the house that night, told us there was no party. jonah says he never doubted the official investigation, but wanted to rebut the theories offered by dina and others. his lawyers hired the highly

regarded investigative firm kroll. the resulting report says, "the evidence is consistent with an accidental, tragic fall, and there is no evidence of foul play, malice or other non-accidental occurrence." how many people said to you, "you need to let this go and move on"? >> so many. >> reporter: 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's attorney keith greer had an eyewitness willing to testify that he saw dina outside the mansion that night. >> and this eyewitness was adamant. he was very clear. no doubt about it. >> reporter: and turned out to be dead bang wrong.

>> and turned out to be wrong. >> reporter: in april 2017, after 4 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 from the hospital and you realize, "i'm wrong and my witness is wrong. dina wasn't there. she was at the hospital provably." >> absolutely. i got mad. i got really mad. >> reporter: greer called a press conference to publicly eat some crow. >> when these pictures come out, though, you can't refute 'em. >> reporter: he removed dina from the lawsuit, along with her sister nina. and the zahau family attorney apologized to you. was that enough? >> he made a public apology. and i would say that not as many people saw the public apology as who saw continuous accusations against us. >> reporter: greer pushed forward anyway with just one defendant -- adam shacknai. that says 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. and a lot of people looked at it that way. >> reporter: 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. >> reporter: in the lawsuit, greer outlined quite a detailed and unsubstantiated narrative. he argued rebecca was killed not to avenge max, but instead, during a sexual assault. greer's theory is that it began when rebecca stepped out of the shower and found adam in her bedroom watching her. >> she then gets uncomfortable and tries to escape. she screams for help about 11:30 that night. >> reporter: greer says that explains the screams heard by a neighbor. >> right after that, to silence her, adam hits her on the back of the head, knocks her at least partially unconscious. then he has time to think and he

grabs the black paint and he paints this phrase on the door. "she saved him. can you save her?" >> reporter: 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 says, "i'm sorry. i'm guilty. i did it." >> yeah. it wasn't staged to be a suicide. >> reporter: even greer says evidence placing adam at the scene is weak. adam shacknai have any marks or scrapes or cuts on him that would suggest he'd been in a struggle with someone? >> none. none. >> reporter: same with adam's 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 loosened the ropes on her wrist to check her pulse. he gave her mouth to mouth resuscitation. he gave cpr pumps to her chest. >> reporter: and there's no dna? >> and how much dna and how many fingerprints are found on the knife, the rope, her body, how much? >> reporter: none. >> zero. zero.

>> reporter: zero of adam's, 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 walked in at court on any case and opposing counsel said, "there is no evidence here, and there is no fingerprints, and there is no dna, and that is the proof of the case that i am bringing," you would think to yourself, "i got a groundball here." >> the absence of evidence isn't the evidence of absence. and so we know it's murder 'cause it's wiped down. we know it's not suicide. >> reporter: would a jury agree0

welcome back. rebecca zahau's death had been ruled a suicide but her sister was convinced she'd been murdered by adam shacknai. adam insisted he tried to save rebecca after he found her hanging from a balcony. now the two were facing off in a civil lawsuit. the jury would decide who was responsible for rebecca's death and the verdict would leave both

sides stunned. >> the plaintiff's attorney got -- he's got a good imagination. >> reporter: adam shacknai says it's simple. he had nothing to do with the death of rebecca zahau. were you present when rebecca died? >> no. >> reporter: did you attack her? >> no. >> reporter: did you sexually assault her? >> no. >> reporter: did you tie those knots on her body? >> no. >> reporter: are those the kind of knots that only a sailor or somebody who worked around boats in the water would know? >> no, those are common knots. >> reporter: sheriff's investigators 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's goin' on here? >> it's denial. it's -- they don't wanna be seen that their -- sister committed suicide. >> reporter: 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 doin' here? >> no. and i have been accused of that multiple times, including the rebecca was depressed and you missed it? >> no. >> reporter: in march 2018, the wrongful death lawsuit began in san diego. defending adam was dan webb, a former u.s. attorney and a veteran of many courtrooms. >> there will be no evidence that shows that adam shacknai had anything to do with the death of rebecca zahau. >> reporter: in particular, no d-n-a 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 adam had cleaned up after himself. >> there was nothing on the door knobs whatsoever as far as prints. >> and that was consistent with it being wiped down? >> yes.

>> reporter: and a handwriting expert who looked at that message on the door. >> the writing on the door more comports with adam than it does with rebecca. >> reporter: greer also claimed rebecca had been sexually assaulted with a knife prior to her murder.