>> i'm natalie morales. and this is dateline. >> i can't even believe she would meet someone at a park at 3 am. i think she knew the second she got in his car that something was wrong. >> a new chapter in a

heartbreaking story. >> i'd like to have a wellness check done on my daughter. >> a secret life uncovered. >> she was on a dating site looking for sugar daddies. >> going into it blindly is not something i would recommend. >> chilling details revealed. >> is this guy dodging us? >> he kind of selected her as his victim? >> correct. >> of course, the bottom of the big site there was a damaged iphone. >> it looks like maybe clothing. it was just a sinking feeling, really. >> i just ripley this one night i had with her and i just want to grab her and say don't do it. don't go. >> hello and welcome to "dateline". college student mackenzie lueck was diving into adulthood, eager to find her path. her family and friends knew her as fun, responsible and always

careful. then one night, mackenzie vanished. a trail of electronic clues helped investigators retrace her steps and exposed a dark underworld were evil was hiding behind webs of lives. here's keith morrison with "the waiting car". >> our minds have a curious way of deceiving us. we sense something off, something wrong. even terrible. and yet, something in the brain wants to believe the worst didn't happen. kennedy stoner knows that feeling well. >> i was kind of pushing away from my gut instinct. i'm not really sure why. i never imagined this ever happening to one of my friends.

>> i wouldn't think you would want to imagine it? >> no, or anyone that i know. so, my mind didn't go there. >> so, she told herself it would be fine, as she reached out from her home here in salt lake city, utah. messages to her friend, mackenzie lueck. >> i saw that she was an opening my snap chats and i texted her. i didn't get a text back. and this is stupid, but i was kind of wondering if she was mad at me for something. >> the mind wants a simple explanation. after all, she knew her best friend was grieving. mackenzie's grandmother had recently passed away in california. >> i know she was heartbroken over that and so was the rest of her family, because they were all very close. >> she went to the funeral? >> she did. she left utah, she went to the

funeral. so, i was thinking maybe she just took a few days off social media or something. >> mackenzie's parents though, hadn't heard from her either. after three days of escalating fear, mackenzie's that made that most dreadful phone call to the salt lake city police department. >> yes, i'd like to get -- if possible, have a wellness check done on my daughter. i've been trying to get a hold of her and her phone just tends to go to voice mail. i was just wondering if i could have somebody maybe go by her house and check on her? >> the story mackenzie's that told was this. on the night of sunday, june 16th, 2019, mackenzie had boarded a flight from los angeles back to utah. arriving in salt lake city around 1:35 am, monday. at 2:01 am, she texted her mom to say she landed safely. after that, three days of silence. two patrol officers went straight away to mackenzie's town house. her car was in the driveway. that was a good sign. repeated knocks at the door, however, went unanswered. peering through a window, the officers saw nothing.

not a soul around. they called mackenzie's dad to report the news. and next, the officers phoned mackenzie's friends, boss and professors. none of them had seen her. all reasons why at the end of this unsettling day, mackenzie 's case was referred to a place that sounded very serious indeed. the salt lake city police departments homicide squad. >> we get a lot of missing persons cases in salt lake city. >> lieutenant todd mitchell was the units chief detective. >> so, i tried my best to sift through those and find the ones that raise that hair on the back of your neck, for the lack of the backer term. and this raise the hair on the back of my neck. so, that's why i decided, yes,

we need to take action now. and at least are on an issue investigation into it. >> through three told, most reports are easily resolved. the missing person may have simply lost their phone or just decided to take a break from some family drama. but that didn't appear to be the case with mackenzie. the relationship she had with her mom and dad would be the envy of most parents. >> they were always contacting each other. they sent silly text back and forth on a daily basis. >> detective and tiffany sayes levitate missing person investigation. even though their specialty was murder. >> we are, the usual homicide investigation, we start, there's a dead party. we were starting with something. we have a victim and we're moving backwards. in this case, we started with nothing. >> first action, sayes and wiley was to pull the salt lake city airport footage from the night of mackenzie's disappearance. and sure enough, there she was. >> so, there is nothing out of the ordinary. we are able to see her come off

the terminal and we followed her all the way down to the baggage claim, where she picked up her luggage. >> seemed perfectly normal, fine, casual? >> yes. nothing out of the ordinary that we can seattle. >> the last clip shows mackenzie, like so many other passengers, casually getting into a car outside baggage claim. but the identity of the driver? a mystery. news of this police investigation quickly spread among mackenzie's friends. >> the second i heard about that, my stomach dropped. >> so, kennedy launched her own investigation. >> i went on facebook. i dropped pictures of us together and i said, she's missing. if you know anything, reach out to me. reach out, police. >> i thought she was still in california. until i saw kennedys message on facebook. >> ashley fine, another of mackenzie's college friends, put up her own facebook posts. >> and i tagged her in it and

because i tagged her on facebook, some of her other family members reached out to me immediately. >> what family members? >> some of her distant cousins. one who lives here in utah and we started talking and messaging. and i said, you know, i have a feeling that she took a lyft share. i feel really strong that she did that. >> so if, you're worried that maybe something happened in that car? >> definitely. definitely. >> on their own ashley and her cousin called lyft and uber, to see even if either one of them had picked up mackenzie at the airport. >> and that's really when this began, because somehow they let it slip lyft did. that she got in a lyft that night. >> what did you do at that point? >> we contacted law enforcement about the lyft. >> a big break for sayes and wiley. because it gave them probable

cause to serve lyft with a search warrant. >> and find out where her destination was, where she was dropped off, what time she was picked up. >> where did she go? >> so, we were able to get the destination from the airport all the way up to north salt lake address and she was dropped off at hatch park in north salt lake, just before 3 am. >> a park? at 3 am? why would mackenzie come here? and just as important, why would a driver leave a young woman alone, burdened with luggage, at a park in the middle of the night? who would do such a thing? it was detective sayes job to track down the driver. who she discovered, was not so easy to find. >> we were like, is this guy dodging us? >> coming up -- mackenzie's friends have a terrifying theory about why she's missing. >> i assumed that the lyft driver abducted her. >> and here's one reason why. >> her last text message that we recovered was at 2:58, prior

to her arrival arriving at the hatch park location. and that was the last activity ever we had on her phone. >> when "dateline" continues. ♪breeze driftin' on by...♪ ♪...you know how i feel.♪ you don't have to take... [coughing] ...copd sitting down. ♪it's a new dawn,...♪ ♪...it's a new day,♪ it's time to make a stand. ♪and i'm feelin' good.♪ start a new day with trelegy. no once-daily copd... ...medicine has the power to treat copd... ...in as many ways as trelegy. with three medicines in one inhaler,... ...trelegy makes breathing easier for a full 24 hours, improves lung function, and helps prevent future flare-ups. trelegy won't replace a rescue inhaler... ...for sudden breathing problems. tell your doctor if you have a heart condition or high blood pressure before taking it. do not take trelegy more than prescribed. trelegy may increase your risk of thrush, pneumonia, and osteoporosis. call your doctor if worsened breathing, chest pain,

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yeah. i respect that. but that cough looks pretty bad. try this robitussin honey. the real honey you love, plus the powerful cough relief you need. mind if i root through your trash? robitussin. the only brand with real honeyand elderberry. >> before mckenzie disappeared in june 2019. the disturbing story had gone national.

several stories about women getting assaulted by using lyft or uber. >> 14 women have filed a lawsuit against the ride share giant. >> perhaps no surprise mackenzie's friend ashley fine imagined something like that or worse. >> i assumed the lyft driver abducted her or maybe they were in a car accident and had their car driven off the road. >> the detective thought that that was a possibility too, so they wanted very much to find that elusive lyft driver who gave her a ride the night she vanished. >> we wanted to know if he was in fact going to be a suspect or not. he was though, nowhere to be found. just as odd, mckenzie's phone, the detectives learned, was turned off just as her lift drive came to an end. >> her last text message that we recovered was at 2:58 prior to her arriving at the hatch park location. that was the last activity ever

we had on her phone. >> on the morning of saturday june 22nd, six days after mckenzie went missing, detectives tracked down mckenzie's lyft driver. >> he says there wasn't a lot of conversation going on in the car, he did recall her being on her phone, but he didn't know who she was talking to. >> was he fully cooperative? >> definitely. he did. he didn't seem like he had anything to do like this at all. >> because he had an alibi, a very good one, actually. as soon as he dropped mackenzie off, surveillance footage at a nearby intersection captured him leaving to pick up another fare, the daytime and location all confirmed by the tracking software on his lyft apps. >> and he continue that throughout the night, and so -- >> you could eliminate him pretty easily based on the fact that he was elsewhere? >> very quickly, yes.

>> she was smiling, she was in good spirits. >> mckenzie's lyft driver, told police and later us that he remembered the weird drop off location, even mckenzie commented on that, he said. >> saying how it was odd to be dropped off in the middle of the night in a park. >> he says that he wasn't worried because someone with a car was there waiting for mckenzie. >> i unloaded her luggage, said goodbye and drove away. >> so who was that someone in the waiting car? the detectives were hoping they could identify him or her through mckenzie's phone records. and she had been texting a number with a two zero six area code right up to the point her phone went dead. >> so, we were able to actually take that number and run it through our little databases, and it came back as absolutely nothing, it came back as nobody.

>> and it had to be some type of burner phone. so whoever that was did not want anyone to know? anyone in any official capacity to know who it was? >> yeah, it was pretty obvious at that point. >> but according to the lyft driver, whoever met mackenzie at the park, made no effort to conceal their identity from them. on the contrary. >> they seem to know each other. very well. i think all i heard was, how are you doing, how is your trip, basic greetings. the situation seemed very safe. she knew the person that she was getting in the car with. >> did mackenzie caught a car with someone that she knew, was both good and bad news? the good news, of course, was that it meant maybe mckenzie went off with a friend somewhere. the bad news? because there was now no proof of a crime, the detectives had lost their power to get any

search warrants. >> we had lost our, what we call, probable cause, that a crime had been committed. >> just like that? >> just like that. >> just because of what the lyft driver said, suddenly you can't be getting warrants for things? >> correct. that was a hard part and it's slow down the investigation at that point, because we didn't have a crime to attach to it, it was still now a missing persons investigation. >> without a warrant, the detectives were blocked from getting detailed phone records, which theoretically, would've shown who mckenzie was texting. so who was this friend mckenzie met at the park? where did they go? >> investigators are about to uncover fresh clues that deepen this mystery, but also give mckenzie's loved ones a glimmer of hope. coming up. one place mckenzie wasn't missing was on social media. >> different people saying, hey, i'm looking at her site right

now and it is showing that she is actively online. >> her bank account was active too. >> so we're hopeful that there could be further transactions on there so that we could find her. >> when dateline continues. my network has gone kaput! (cecily) oh, you tried to save a buck on it? (einstein) i got what i paid for. not so smart. (cecily) nah, you're still a genius. but, there is a smarter way to save. (einstein) oh?! (cecily) switch to verizon! for a limited time, get welcome unlimited for just $25/line. (einstein) $25?! (cecily) and it's guaranteed for 3 years! (einstein) brilliant! (cecily) well, you would know. (einstein) i'm switching! (cecily) i think the bike's probably faster. (vo) now is the best time to switch to verizon. for just $25 a line. guaranteed for 3 years. the savings that last. on the network you want. verizon. power e*trade's easy-to-use tools make complex trading less complicated custom scans help you find new trading opportunities while an earnings tool helps you plan your trades and stay on top of the market moderate-to-severe eczema. it doesn't care if you have a date,

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why did mackenzie go to a park eight miles from home at 3 am, no less.

who did she meet? it made no sense. to her friend ashley fine. >> i can't even believe she would meet someone at a park at 3 am. it's just so unlike her. >> it is? >> so unlike her. >> because mackenzie, like most of her sorority sisters, talked a lot about safety. >> i mean, i've been out with her a lot of times and she's always been extremely safe. she's texted me after going out at night and said, hey, did you make a home? are you okay? >> you had exchanged things just to keep each other safe? >> yes. >> ashley had met mackenzie almost four years earlier. >> she was a little bit shyer than most people would think she would be. but once you got to know her, she had a big personality. she could make anyone laugh. >> kennedy stoner also met

mackenzie in college. >> her family doesn't live here, so she was all on her own here. so, she got a job, she was going to school. she was checking off everything that a responsible adult would have on their checklist, i guess. >> mackenzie grew up near los angeles, el segundo, california. and she was raised in the church of latter-day saints. but when she came to the university of utah to study kinesiology, according to ashley, mackenzie did not exactly remain devout. >> i know she was registered here in salt lake city, i heard she was never active. and that made sense to me because i think she wanted to find her own path. >> you saw her changing? >> yes. >> in recent times, didn't you? >> in what ways? >> i think she was trying to almost gain confidence and security in herself. she'd always write herself notes saying how she wanted to feel more confident, because i think she realized she was really shy, and she wanted to be more outgoing and to meet people. and she wanted to explore dating, and it might not be how

everyone else thinks that dating should be. >> what ashley is getting at is that mackenzie was active on dating sites. so much so that by saturday, june the 22nd, the sixth day after mackenzie's disappearance, detectives had received several phone calls from some of the men mackenzie met online. mainly to say they had nothing to do with her disappearance. >> i mean, nowadays that's how people meet people. so, while it was of significance because it gave us one more thing to look at, it wasn't this big, huge red flag either. >> so, was mackenzie off on a lark with a guy she met online? a hookup she wanted to keep secret from her devoutly religious parents? well, that certainly seemed far more likely than some sort of kidnapping scenario. >> she could've gone camping, or gone with a friend, where they would lose cell-service,

and it wouldn't be out of the ordinary. >> but when they did some checking around that camping idea, it seemed a lot less likely. by standard procedure, they looked up airline flight records and discovered mackenzie had been booked on a flight out of town to los vegas. so, maybe she was there. and meanwhile, the detectives began to see activity on her bank account. and something else. >> different people saying, hey, i'm looking at her site right now and is showing that she's actively online. >> so, maybe she was just fine. ignoring the fuss, or zoned out entirely unaware of it. >> so, we were hopeful. >> sure.

>> because when people go missing, even if it's on their own accord, they're still going to be bank transactions or paying for stuff. so, we were hopeful that there would be further transactions on there so that we could find her. >> not far from the police station, kennedy and ashley hosted a rally to make sure everyone in salt lake city knew to be looking for mackenzie. >> hey, guys, this girl is missing, and we're looking for her. she could be in danger. we think she's in danger. >> but was she? on sunday, june the 23rd, detectives learned mackenzie had a flight booked for that very day, traveling from las vegas to los angeles to attend a friend's wedding. >> she wouldn't miss that. so, we contacted los angeles police department and they had officers waiting for that flight to land. >> they waited by the jet way for all the passengers to de-plane. mackenzie was not among them. then they learned this. it wasn't mackenzie who'd been logging into her social media accounts. that had been her friends. >> they obtained her email password, and they were not doing it to try to ruin things or anything, they were trying to go on there to monitor the

sites as well to see if any information could come up. >> and the activity on mackenzie's bank account? >> it was the lyft transaction on the 17th and then an automatic payroll deposit from her work. >> and then the detectives got a tip from -- this guy. who, just maybe, could bring all of those blurry details into sharp focus. >> coming up -- >> i got on the computer and within an hour, two hours, i had found her profile. >> the world of sugar babies. >> i think we're living in a culture where it's much more accepted and embraced for women to be upfront about what they need and want. >> did know mackenzie what she was getting into? >> a lot of people who go into it are seriously so blind to the whole reality of what it is. >> when "dateline" continues. it was time for a nunormal with nucala.

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lunar new year celebration at a dance hall in monterrey park california. police say the suspect, at the 72-year-old man died by self inflicted gunshot wound, a motive is under investigation. and just an hour later in baton rouge louisiana, 12 people were injured after gunfire erupted in a nightclub sunday morning. all of the victims were hospitalized and in stable condition. now, back to dateline. dateline. >> welcome back to dateline, i'm natalie morales. where was mackenzie lueck? the college student took a lyft to meet someone at a park at 3 am. but who? mckenzie was active on dating sites making police wonder if her late night rendezvous was a hook up, and her radio silence was intentional. now a tipster was about to share troubling details of his encounter with mckenzie shortly

before she went missing. here's keith morrison with the waiting car. >> it was a few weeks before mckenzie vanished, a meeting at a bar, with this man rob joseph. >> she seemed like a very bright, bubbly girl friendly. >> they talked for more than an hour said robbed or she did while he listened. rob is an ex-cop, which of course he told her. >> if you mention you're an ex cop in you're a pi, everybody all of a sudden wants to tell you they're dark secrets or risky behaviors. >> it's not how people react, really? >> yeah. you would be surprised. people just want to tell you things that you don't want to hear. >> anyway. he only saw mackenzie that one time, he said. didn't get her phone number and

-- >> i didn't offer my number, i usually don't give out my number. >> and that was that, he said. he didn't expect to see her again. but, just three weeks later. mckenzie was missing. rob said the friend who was with him at the bar that tonight made the connection. >> he just mentioned to me casually, that girl we met at the bar, that's the girl that went missing. >> of course rob remembered the student and the secret she revealed to him that night. >> i don't know whether she was seeking approval or just advice or recommendations -- >> how did she put it? >> she said she was on a dating site and looking for sugar daddies and i asked her which ones and she said seeking arrangements. >> seeking arrangement, a wet side designed to connect young women with prosperous old men. robert newell lot about dating sites, he is a p. i., remember?

he figured if mckenzie was missing, that just might have something to do with it. >> i went straight home got on the computer and got on to seeking arrangement and within an hour, two hours i had found her profile. >> there she was, beach baby 96. >> what was interesting about her profile is that it was very authentic and honest. she wasn't really hiding who she was, she was pretty specific about -- 23-year-old, grad student studying kinesiology, california girl. likes to drink wine, likes to go out, likes to travel, looking for somebody to do that with. >> a little bit more pg than some of them, maybe? >> yeah. >> soon as he founded he sent a screen grab of mackenzie's profile to the salt lake city police department. >> this was definitely another avenue that we had to look at, and track down anybody who might have been in contact with her. >> mckenzie appeared had compartmentalized information about her life. >> the plane ticket to los angeles, for instance had been paid for by man she had met

through seeking arrangement, and a 300 dollar deposit to one of mackenzie's bank accounts? >> that was from one of her other dates that she had been on that she had received a payment from. and that was prior to her go bring over to her grandmother's funeral. >> her friend, ashley, said she didn't have a clue. >> i didn't know anything about her being on that site -- >> she didn't talk about it, it wasn't like a start a conversation? >> not with me. >> mckenzie spring kennedy wanted to avoid the subject altogether. but she acknowledged that seeking arrangement is well known on campus. >> the site is not unfamiliar to a lot of women and in women in college. >> everybody knows about it? >> every knows about the site. >> seeking arrangement was founded in 2006 by a self proclaimed nerd and mit grad name brandon wade. he declined our interview request but in this 2016 today

show story wade said he came up with the idea as a way to meet young women. >> the average sugar baby is roughly 27 years old, 50% of them are college students, they are ambitious, they are beautiful and they are on the website because they want to find somebody who is successful who will help them or spoil them. >> i think we're living in a culture where it is much more accepted and embraced for women to be upfront about what they need and want. >> journalist mary ella moss novel writes about sex and culture, and sees sugaring as a form of female empowerment >> and, to hold power in a way that is open that is less stigmatized that it has been in the past. >> so they see this as holding power? >> i see it is very powerful, yes. >> explain that a little bit. >> anytime you go into a relationship of any kind saying this is what i need and if you can't give me this i'm going to

move on, it's a powerful thing to say. >> there is some debate about this, whether it actually empowers young women or exploits the innocent. >> i mean, a lot of people who go into it are seriously so blind to the whole reality of what it is, you know? >> like mckenzie, she had a seeking arrangement profile but unlike mckenzie, she told us that she was anything but a new be when we spoke to her in 2019. >> at the time the 20 something had been with a sugar daddy for six months, he was 63. do you mind telling me how much he paid you? >> my allowance is 1200 a month. >> she told us it took her a long time to find and arrangement. >> you have to fished through all of those guys who like, literally, say let's meet up at a hotel, have sex and i

prostitute. >> shades of gray could be confusing for anybody said it asia, let alone a novice on seeking arrangement. >> i've seen girls who have had sugar daddies they're not even the same person after. >> did you read a mackenzie's profile? >> yes i. did >> she came from a sheltered upbringing, would that have made it more dangerous for her? >> most definitely. going into it blindly is not something i would recommend. like at all. >> welcome to elects top sugar, in this episode, it's all about getting ready for your sugar date. >> seeking arrangement does make what they call let's talk sugar videos, they offer advice to novice sugar babies giving tips on everything from how to ask for an allowance, to what to pack in your purse. perfume they say, and pepper

spray. >> not that you'll need it on your date, but, going out looking hot is always a risk. >> did mackenzie watch to the videos, we don't know. but one of her decisions said deja betrayed her lack of experience. >> why would you meet in the middle of the night, in a park? >> and there was something else, whether mckenzie did it or the person she met, we don't know, but remember right after the lyft driver dropped her off at the park, someone turned off mckenzie's cell phone. which happens to be contrary to seeking arrangement most important rule. >> you never want to get stuck phoneless, that is your lifeline. >> mckenzie lost her lifeline, but before it went silent she was busy texting, soon investigators would follow her digital trail to the elusive man who received those messages. coming up.

>> we got an ip address that comes back to his residence. >> tracking text messages. >> he said all have an open wi-fi because i run an airbnb business. and so it could be anybody. >> did he run an airbnb business? >> and a tip from a concerned neighbor. >> she described it as just being a really offensively smoky and odorous -- >> when dateline continues. feeling better? on top of the worlddddd!!! before advil. advil targets pain at the source of inflammation. when pain comes for you, come back fast with advil liqui-gels. ♪♪ ready to feel what it's like? when you can du more with less asthma. it's possible with dupixent. dupixent is not for sudden breathing problems. it's an add-on treatment for specific types of moderate-to-severe asthma. and can help improve lung function for better breathing in as little as two weeks.

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we're trying to find out if mckenzie lueck's disappearance was voluntary or not. remember the flight she was supposed to be on to los angeles? they found out it had been paid for by a sugar daddy, but remember, mckenzie wasn't on that flight. and they found out she wasn't on the one to vegas either. >> it was at that point that we were able to say okay, we have enough here that we can build our probable cause back up and really start serving some search warrants again. >> and off the detectives when, in search of the mystery person mckenzie was texting the night she vanished. >> with the 206 area code, conversations going well before she left l. a. to all the way where she ended up in hatch park. >> that digital trail

eventually led them to a wi-fi router at this salt lake city house, owned by a man for named ayoola ajayi, ex national guard, successful tech worker, part-time model. police knocked on aj's door talked with him and found he was friendly, helpful, sure he said he had girlfriends, but mackenzie they showed him a photo and he -- >> he said he had never seen that lady before. >> so, why then, the police asked, did mackenzie get tex routed to aj's wi-fi system? >> he says i have an open wi-fi because i run an airbnb business. and so it could be anything, anybody from here. >> did he run an airbnb business? >> yes he rented out the two bedrooms in his basement for airbnb. >> they looked around, saw nothing amiss and left. and then, that same evening aj stopped by the police station

to say that he discovered something. and that he had texted with mckenzie lueck the night she disappeared, he had forgotten because mckenzie was the one who reached out to him without identifying herself. maybe, he said, she had seen his seeking arrangement profile. >> so i think that's how she met -- on my profile. >> so she just texted your number? >> yeah. >> he said he had no idea who it was. >> you're still saying that, that's the only text, that's the only messages you got from her, right? >> that i can remember. >> so about, perhaps it just sent me a question mark that i might have talked in the past. >> but she blew him off he said, ghosted him, so he forgot all about it. but he told that story with so much confidence, too much maybe. >> we had two different things, we have an ip address that comes back to his residence and

now we know that he had contact with her. >> except, there was no proof mackenzie had been abducted by a. j. or anyone else for that matter, so he was free to leave. but before doing so, he gave the detectives his cell phone number, just in case they needed to get a hold of him. his cell number registered in his name. remember police didn't have that before, they just had that bogus two zero six number used by the texting app. so now, with aj's personal cell number, they could get a search warrant for his calls, and two days later. >> we got the confirmation back from the fbi that mckenzie's records were showing her going from the airport to hatch park and a.j.'s records were showing going from his residence and also meeting up at hatch park at the exact same time. >> and that was enough to get a

warrant to search a.j.'s home, where investigators noticed a mattress was missing from the bedroom, and there was a strong smell of bleach. he also spoke with a concerned neighbor, her face blurred in this video. who wanted the police learned that he had started an illegal backyard fire. >> she described it as being and offensively smoky and odorous. >> debris even flew into the neighbor's yard. >> it looks like there was clothing, pieces of maybe fake leather, vinyl, we weren't sure what it was. >> what was it like for you when this discovery was made? >> i don't even know how to describe, but it was just a sinking feeling, really, it's like we want to know what happened, but also we don't want to know what happened. because if it is what we think might have happened, we don't want to know what happened. >> coming up. >> that's probably the hardest part in the investigation was

watching him walk out the door that night. >> hard for detectives, but it gave mckenzie's friends reason to hope, -- >> maybe can see was alive and he was hiding her, because the police let him go. >> when dateline continues. crohn's disease. now, there's skyrizi. ♪ things are looking up ♪ ♪ i've got symptom relief ♪ ♪ control of my crohn's means everything to me. ♪ ♪ ♪ control is everything to me. ♪ feel significant symptom relief with skyrizi, including less abdominal pain and fewer bowel movements at 4 weeks. skyrizi is the first and only il-23 inhibitor for crohn's that can deliver both clinical remission and endoscopic improvement. the majority of people on skyrizi achieved long lasting remission at 1 year. serious allergic reactions and an increased risk of infections or a lower ability to fight them may occur. tell your doctor if you have an infection or symptoms, had a vaccine or plan to. liver problems may occur in crohn's disease.

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everyone should have it and now a lot more people can. so let's go. the digital age is waiting. i screwed up. mhm. i got us t-mobile home internet. now cell phone users have priority over us. and your marriage survived that? you can almost feel the drag when people walk by with their phones. oh i can't hear you... you're froze-- ladies, please! you put it on airplane mode when you pass our house. i was trying to work. we're workin' it too. yeah! work it girl! woo! i want to hear you say it out loud. well, i could switch us to xfinity. those smiles. that's why i do what i do. that and the paycheck. welcome back. police finally discovered mckenzie was texting before she went missing. a man that won by a. j..

he told detectives that they never met in person. cell phone tracking data placed him at the same park and at the same time that mckenzie vanished. now investigators were closing in on their suspect, but were they any closer to answering the crucial question, where was mackenzie? here is keith morrison with the conclusion of the waiting car. >> police looking for mackenzie lueck heard it is there being story. from a neighbor who said aj had sent a suspicious fire. the neighbor had found debris in her backyard. so they looked in aj's backyard and found something else disturbing, a freshly dug patch of soil. they called in a cadaver dog, which gave the unmistakable evidence, human remains. aj calmly watched it all from his driveway was taken into

custody. a team from the crime lab spent the night digging up the backyard. they found more burnt clothing, purses and back packs, and then, down towards the bottom of the site, there was a burned and damaged iphone. the medical examiner identified human tissue. >> just fragments, mind you. they could not be certain who or what they had, exactly. >> we had tissue samples, or pieces, so, in order to charge somebody and arrest them, that needed to be confirmed. we knew that would take time. >> so, without solid proof a murder had been committed, they once again, reluctantly, let aj go. >> that was probably the hardest part in the investigation, watching him

walk out the door that night. >> mckenzie's friends heard that he was released. it took it as a sign of hope. >> that maybe mckenzie was still alive, and he was hiding her because the police let him go the next day. >> then, at daybreak, detectives got a call from the state crime lab about the remains found in the backyard. >> they were able to identify that as been consistent with mckenzie. >> the swat team took aj into custody. police called a press conference to announce his arrest. >> we are filing charges of aggregated murder and homicide on mackenzie lewis. >> her friend was watching on her cell phone. >> i almost blacked out, or something. i dropped my purse, my phone, and then i drop to the ground on the street. i was just balling. >> i could not even believe it. i still can't believe it. >> but the detective work was not done. although they found human

tissue in the fire pit that linked it to mackenzie, they had not found her body. so the investigation continued, and, once again, aj's personal cell phone gave it away. remember when he first spoke to police about mackenzie. the very next day, his cell phone pinged it's way up into these mountains. >> about two months north of here and then goes partially up to the canyon, then returns back to salt lake city a couple hours later. that was odd to us. >> had he, a nervous killer, exhumed her body from the backyard fire pit to rebury her up here?

they set off the search logan canyon. >> it took us the better part of a day until we found her. >> that has to be another part tough part of your job? >> it was horrific, a sight that none of us wanted to see. >> the search for mckenzie was over, but the investigation was not. >> in the weeks following, a woman came forward to say that she had been sexually assaulted by a. j. a year earlier. >> at aj's residence, the same residence where mckenzie was killed. >> she said that she met him through a dating app, a religious one. aj was charged with aggravated kidnapping and forcible sexual abuse in that case. the evidence was tightening around him, evidence of what he did to mckenzie was growing. finally, october 7th, 2020, a. j. pleaded guilty to murdering mackenzie lewis. as part of his plea deal, he admitted that he thought about

killing mackenzie, and then he planned the killing of mackenzie, a thoroughly premeditated murder. >> that he knew that he was going to murder mckenzie before she even touched down at the airport -- >> he selected her as his victim, right? >> right. >> was there any explanation at all of what is motivation was to do it? >> none, he never offered any reasoning as to why. or even how. >> aj also pleaded guilty to sexually abusing his first victim. he was sentenced to life without parole. one more thing, said the detectives, he was active on the seeking arrangements site right up until he was arrested. >> even after we made contact with him, he was still on that page, still trying to get a date. >> we don't know why, some selfish jerk used his position on a dating website to somehow ensnare this bright, pretty woman, and for what? >> you look at his profile page, he comes across as a gentleman,

somebody that he truly is not. that is the whole cautionary tale is that you never know if they are actually say they are. >> always, she had been surrounded by people who loved her, worried about her, cared about her. mckenzie was an innocent, setting out, if only for a moment, for new possibilities, unaware that in the world she was entering, the innocent could also be prey. >> that is all for this edition of dateline, i'm natalie morales, thank you for watching. they were kind of a romeo and juliet couple. trying to run away together. in the tragedy of it all going so terribly wrong. >> a mystery hiding in a lake.