>> something's wrong. something's bad wrong. >> where was skylar. someone was hiding something. >> it was the fbi. they were serious. >> twitter, instagram, facebook. you just see things. ridiculously out of control. >> a clique of mean girls. were they mean enough to kill? >> she was like, well, she'll blackmail me. >> it was such a shocking and scandalous kind of case. >> this was diabolical. >> evil comes in all shapes and sizes. >> hello, welcome to "dateline." for skylar's parents, she was all they hoped for. a straight-a student and happy at her part-time job. then their world turned upside down when their only child seemed to vanish without a trace. at first, police thought she ran away. but hits on social media would point to a more sinister reason for her disappearance. here's andrea canning with "something wicked." >> in the gentle rolling hills of northern west virginia, in a sweet college town in the heart of coal country lived three teenage girls. their photos capture a moment in time. they were smart, talented, lovely. everything a parent could hope for in a daughter. and so who could have guessed just by looking that some of them carried a dark secret about a friend. >> 911. do you have an emergency? >> i have a 16-year-old daughter. she has not been home, hasn't went to work. i'm scared to death. >> these teens played a strange and haunting game. >> would you rather suffocate or get shot? >> get shot. >> a game of betrayal that went way beyond typical teenage drama. >> she's calling out help me. you know, why, why, why. >> at the center of it all was a girl named skylar. david and mary neese welcomed their only daughter skylar to the world in 1996. tell me about the day she was born. was that the greatest moment of your life? >> i wouldn't go that far. >> first time you saw her. >> first time i saw her, yes, i can say that was the greatest moment of my life. yeah. it was instant love. >> they live in star city, a small suburb ever morgantown, west virginia, where dave works at walmart and mary at a medical office. skylar was a whirlwind, a rambunctious, precocious toddler who owned her parents' hearts. >> hey, gorgeous. >> hi, daddy. >> you're beautiful, baby. >> she was reading way before she was supposed to, doing math and stuff way before she was supposed to. she was a very intelligent little girl. >> dance for me. wee! >> when skylar started nursery school, she made her first friend, morgan lawrence. morgan was drawn right away to skylar. >> did she kind of light up a room? >> oh, yeah, she had the giggle and the laugh. >> the girls' families became good friends. dave and sheryl say morgan and skylar were like sisters. >> what are your memories of skylar when she was this high? >> she giggled all the time. it just filled our house. >> she had the biggest eyes. you'd just want to hug her. >> they were good girls, got good grades. morgan dreamed of becoming a meteorologist. skylar a criminal lawyer. they also had a pact, that they would always be there for one another. and you would both be in each other's wedding parties. >> everyone has a sister to put in their wedding, and we had each other. >> as freshmen at morgantown's university high school, the two girls drifted apart a little. with a new school came new friends. classmate daniel said the bubbly skylar fit in right away. >> friends came first. she was always about hanging out with friends if she didn't have work or school. >> soon, skylar had two new bffs, sheila eddy who the meeses had known for years and rachel shoaf, a striking redhead with broadway aspirations. it wasn't long before they were calling themselves the three musketeers. and in pictures they looked the part. >> they were literally together every second of every day, it seemed like. they hung out all the time. >> and like all teenage girls they shared videos and photos with each other and online. >> giving us a glimpse into their world. skylar and sheila just having fun. >> let me try to go on your back. >> and of course they occasionally got into trouble, but even then it was for typical teenage things. dave and mary weren't too concerned. >> she is a straight-a student who loves her parents. did you sort of chock it up to, we're not thrilled but she's a teenager? >> exactly. >> when summer rolled around after her sophomore year, skylar seemed happy. she had a job at wendy's which she loved. on thursday july 5th, 2012, she came home after work and got ready for bed. >> she put her arm around her mom, gave her a kiss and hug and said, i love you, mom, turned to me and said, i love you, dad, and she went to the room. >> the next day, dave planned to meet skylar in their apartment at lunchtime. he was surprised she wasn't there. a little worried he called mary. >> i thought she was out with one of her other friends. i figured they went swimming and shopping. >> dave called her friends including sheila. no one had seen her. next he went outside and found more cause for worry. a small bench was tucked near skyler's window, and the window screen was missing. >> at this time i called skyler's cell phone. i said, hey, you're in trouble. you better be calling me right away. so i called her cell phone about ten times. i called mary again. >> again mary told him to calm down. she said skylar was expected at work at 4:00. >> i said, we're not going to worry. i'll call them about 10 after 4:00, give her time to clock in, everything, see if she's there. >> but mary didn't get a chance to call wendy's. >> they called us first wanting to know if she was coming to work. >> was that a big moment for you? >> yeah. >> a few minutes later, there was another big surprise. a call from sheila. >> she said she had to tell me the truth. i said, well, what truth? she said, we snuck out last night. >> mary's heart fell. skylar had done that once before, gone on a late-night joyride with rachel and sheila. that time they were caught for being out after the town curfew. now here was a worried sheila saying they had done it again. >> i said, where did you go? where is skylar? she said skylar insisted they drop her off at the end of the street so we wouldn't hear her sneaking back in. >> now that missing screen and bench outside skyler's window made sense. skylar had put it there to boost herself up so she could get back in. but it left them with a terrifying possibility. >> my first instinct was, someone abducted her from the end of the street to our house. >> dave called the police. >> i have a daughter that's 16 years old. apparently she snuck out of her room last night and she hasn't been seen since. none of her friends can gotten ahold of her. i can't find her. >> what's her name? >> skylar. >> their world had fallen apart. their only daughter had been gone for almost 24 hours. where was skylar? >> reporter: the investigation begins and concern for skylar begins to grow. coming up -- >> feeling in my heart that something terrible had happened. >> mary told me that night, she said, something is wrong, babe, something is bad wrong. >> reporter: a grainy piece of videotape is about to give police one giant clue. what can they glean from this. >> she slowing walked down to a car and got in the back seat. >> when "dateline" continues. ♪ all the way out here just for a blurry photo of me. oh, that's a good one. wait, what's that? that's just the low-battery warning. oh, alright. now it's all, "check out my rv," and, "let's go four-wheeling." maybe there's a little part of me that wanted to be seen. well, progressive helps people save when they bundle their home with their outdoor vehicles. so they've got other things to do now, bigfoot. wait, what'd you just call me? bigfoot? ♪ my name is daryl. is skincare from around the wobetter than olay? olay regenerist faced 131 premium products, from 12 countries, over 10 years. olay's hydration was unbeaten every time. olay, face anything. people are surprising themselves the moment realize they can du more with less asthma. thanks to dupixent, the add-on treatment for specific types of moderate-to-severe asthma. dupixent isn't for sudden breathing problems. it can improve lung function for better breathing in as little as 2 weeks and help prevent severe asthma attacks. it's not a steroid but can help reduce or eliminate oral steroids. dupixent can cause serious allergic reactions including anaphylaxis. get help right away if you have rash, shortness of breath, chest pain, tingling or numbness in your limbs. tell your doctor if you have a parasitic infection and don't change or stop your asthma treatments, including steroids, without talking to your doctor. du more with less asthma. talk to your doctor today about dupixent. if your financial situation has changed, we may be able to help. if yit's very common to havehave has changedsensitivity a gum health concern as well. you know, i talk to dentists every day and they're able to recommend new sensodyne sensitivity & gum. it's really good dentistry to be able to recommend one product that can address two conditions. star city, west virginia, has just 1,800 residents, only one stoplight. >> skylar going missing was a tough pill to swallow for the entire community. >> police officer jessica coalbank got the skylar neese case. >> first impression was it could be a runaway. there are kids that run away all the time. >> it wasn't long before officer coalbank got the video from the security cameras at the neeses' building. skylar's friend sheila eddy said skylar was home around midnight. so what was this car doing pulling up around 12:30 a.m.? who was in it? dave neese watched horrified as there on the tape out walked skylar. >> she slowly walked down to a car that was sitting there waiting on her. she got in the back seat. i could tell that. and she drove away. >> police couldn't quite make out a license plate or tell the make or model. skylar's mom mary had a theory. >> she made it home, snuck back in the window, then a second person or persons had parked behind the building and she snuck out a second time. >> but why? who was in the car? and where did they go? the police didn't issue an amber alert because it looked like skyler left voluntarily. >> once the video came out that she willingly got in this car, they're not going to come out and look for someone driving in a car. >> skylar's friend sheila came over. >> she spent a lot of time telling us, it will be okay. she'll be home. i really miss her. i love her. i want her back. >> the next day, sheila sat with mary on skylar's bed, both of them crying. >> did it bring you comfort when sheila would come by, being skylar's best friend? >> it did me a little bit, yeah. knowing, how could skylar leave her behind? >> mary and sheila took to the streets together, posting flyers for skylar. >> they would knock on doors and ask, have you seen this girl? we kept showing the picture to people. nobody had seen her. >> sheila was very, very worried about what had happened to skylar. >> chrissy swanson is a close family friend of sheila's and saw sheila's distress firsthand. >> she was trying so hard to help them find anything, so hard to help them figure out what had happened. >> the star city police are still looking for a missing 16-year-old. >> dave made a plea for help on local news station wboy. >> we love her. we want her home. >> by sunday night, skylar had been gone the whole weekend. her family, including her aunt carol, was heartsick. >> i just had this horrible feeling in my heart that, you know, something terrible had happened and it wasn't like her to run away or disappear like she did. >> mary told me that night, she said, something's wrong, babe. something's bad wrong. >> the community held a candlelight vigil. skylar's school friends came, including rachel and sheila. >> they were crying, came up and hugged me and mary, just crying their eyes out. >> the only thing mary could say was, what can we do to help these girls? how can we help these girls? >> skylar's family friend morgan lawrence was upset too. she was at camp when she read on facebook that skylar was missing. >> how worried were you? >> sick to my stomach worried. >> so was officer coalbank. she was at it nonstop. >> i'd come back to the office in the evenings, watching video, getting facebook records. >> she got swamped with tips saying they'd seen skylar. from morgantown to new york and even california. each sighting was a dead end. at the same time, coalbank pulled skylar's records. what she found was ominous. skylar wasn't using her cell phone or atm card. coalbank now had serious doubts skylar had run away. >> usually runaways take items with them they want. especially if she had contacts or glasses. she didn't take that stuff with her. >> then police got an important new lead in the case. there had been two bank robberies in the nearby town of blacksville. both of them had gone down around the time skylar vanished. >> i was working with investigators on the bank robberies. >> while looking into the robberies, ronnie gaskin of the west virginia state police was called into skylar's case. there had been a tip that skylar had been at a party with the suspected bank robbers when something bad happened. what was the theory? >> they were just rumors, gossip going around there was this teenage party, that there was a possible overdose, and people there were scared so they hid the body. >> it seemed unlikely. skylar didn't use heavy drugs. >> it was just a lot of tracking down rumors. tons and tons of rumors. >> all leading nowhere. by now skylar had been gone for more than a month. gaskins vowed he would find her. >> i don't like to make promises in my line of work but the only promise i made was we would never give up in trying to find out what happened to skylar. >> their search for skylar had taken them across the united states. what they didn't know then was that the truth was right there in morgantown at university high. coming up -- >> i started posting on facebook things about karma, karma will get you. you can't hide. >> twitter, instagram, facebook and things start to get ridiculously out of control. >> whispers in the hallways. was someone hiding something? police are about to get a break. >> that was an aha moment. finally we have something to go on. >> when "dateline" continues. the first day of school the fall of 2012 was heartbreaking. one of university high school's top students, skylar neese, had disappeared during the summer. classmate shania ammon. >> starting school without her, that was probably one of the hardest days through the whole thing. skylar was just a go to person and she was gone. >> skylar's friend morgan lawrence was dreading roll call. >> i didn't have any classes with her, thank god. >> you didn't want to hear her name called. >> it's not the same. i know you can't tell the teacher we don't know if she's coming back. >> in some ways, life seemed normal. skylar's good friend sheila eddy seen in this video taken in the classroom is back in school. >> i don't want my baby to look like him. >> so is bff rachel shoaf >> rachel got the lead in the fall play. but everyone was worried about skylar. and in school hallways and on social media, rumors flew. >> between twitter and instagram and facebook, you just see things start to get ridiculously out of control. >> kids saying things from skylar had overdosed and things that skylar is in a different country. >> daniel hoevatter was in drama with rachel and knew how close the three girls were. he wondered if rachel and sheila might be helping cover something up for skylar. >> there had been rumors going around, rachel and sheila know where she's hiding. >> daniel knew rachel and sheila were the last ones to see skylar and wondered if they were protecting her or maybe protecting someone else. either way, they had to know something. >> there were probably a good three, four, five times where i told rachel, if you know anything, you need to say what happened or where she's at. >> daniel wasn't alone. this couple live in the morgantown area and have written a book about skylar's case and spent hours combing through what kids were writing on social media. >> the one thing that stood out to me is that people, teens, were tweeting sheila and rachel had to know something. >> why don't you guys just talk, just say something? tell us what you know. >> the heat got turned up on the girls when the fbi showed up and started interviewing students. >> i was only interviewed once. i guess i was nervous because i was like it's the fbi, like they're serious. they asked me about rachel and sheila, if they seemed any different and i was telling them they didn't seem different but they were secluded to themselves more. >> the normal fall rituals were punctuated with police visits to rachel and sheila. kids say rachel left play rehearsal to meet with the fbi. mary and dave neese desperate to find their daughter thought the police were wasting their time investigating the girls they knew so well. >> went to the police and said will you leave sheila alone, please. you guys are harassing her 24/7. the kid is going through enough. leave her alone. she was like our daughter. >> investigators were convinced the two girls knew more than they were saying. that fall, ronnie gaskins interviewed each girl repeatedly. how was sheila's demeanor in these meetings you'd have with her? >> calm. collect. would look at you right in your face, in your eyes. >> he says rachel seemed distracted. >> she would draw on the desk, play with the pencil. just her nonverbal cues spoke a lot. >> their story never varied. they picked skylar up, drove around morgantown, smoked a little pot, and dropped her off a few blocks from home. >> it was like a recording with these two. >> in the meantime, the officers had begun to collect physical evidence, and it didn't match up with the story the girls had been telling. surveillance video from a convenience store put the girls' car not heading east as they had said but heading west towards blacksville. and the girls' phone records from that night showed rachel's phone pinging off a cell tower in blacksville. >> that was an aha moment. finally, we have something to go on that's different from their story. >> now even skylar's parents joined the chorus of people trying to get the girls to talk. >> i started posting on facebook things about karma, karma will get you, you can't hide. we were pushing. we were pushing the girls to get them to say what happened. >> by late november, the pressure seemed to be taking its toll on rachel. in an interview, she surprised police by changing her story. admitting for the first time that they did drive to blacksville that night and that's where skylar told them to let her out of the car. blacksville, where those bank robberies had happened. the next day, sheila changed her story to say the same thing. >> that must have been a big red flag for you. >> absolutely. >> at school kids say rachel was increasingly rattled. >> rachel seemed distressed. she seemed like she was very upset over something. i mean, this was eating at her heart. >> rachel shoaf was about to crack. coming up -- >> please hurry. >> an emergency at home. and an interview with police. what exactly was rachel shoaf about to reveal? >> we were speechless. >> reporter: when "dateline" continues. y face! hpv can cause certain cancers when your child grows up. get in its way. hpv can affect males and females... and there's no way to predict who will or won't clear the virus. but you can help protect your child by taking a first step. the cdc recommends hpv vaccination at age 11 or 12 to help protect against certain cancers. hey cancer! not... my... child. don't wait... talk to your child's doctor about hpv vaccination today. don't wait... when you drink or eat something that's acidic everyone is at risk for enamel loss. it sucks the minerals out of the tooth's surface. pronamel is formulated to help deliver minerals to the tooth's surface to help reharden and strengthen your enamel. at walmart. hello. i'm dara brown. here's what's happening in the united states. more than 3.7 million people have been infected with covid-19. over 140,000 americans have died from the virus. a record-breaking 147 deaths in just one day. flags were lowered to half-staff today at the white house, the capitol and all federal properties to honor civil rights icon john lewis. he lost his battle with pancreatic cancer on friday. now back to "dateline." >> reporter: welcome back to "dateline." i'm natalie morales. in the months after her disappearance, skylar niece's parents were -- many wondered if her bffs, rachel and sheila knew something. investigators were convinced of it. both girls were sticking to the same story. that was about to change. one of them was ready to talk. here's andrea canning with more of "something wicked." christmas 2012 came and went for skylar neeses' parents. dave and mary. it had been six months since their daughter disappeared. the holidays must have been very hard that year, christmastime. >> we didn't celebrate. >> nah. we didn't put up any tree. we didn't do anything. >> just another day. >> yep. >> around that time, rachel shoaf and sheila eddy stopped attending university high. their few remaining friends told the authors that rachel seemed agitated. >> she was acting out, getting into more family altercations at home. >> so the walls were closing in on rachel. >> uh-huh. >> 911, we have an emergency. >> i have an issue with a 16-year-old daughter of mine. i can't control her anymore. >> then on december 28th, rachel apparently snapped. her upset mother called the police. >> she's screaming. she's running through the neighborhood. give me the phone. this is over! this is over. my husband is trying to contain her. please hurry. >> and rachel was taken to a mental health facility. a few days later, corporal ronnie gaskins got a big surprise. rachel wanted to meet at her lawyer's office. she had something she wanted to say. >> take us inside that attorney's office with rachel. what was her demeanor? >> i remember her pulling up the wastebasket next to her. she was afraid she was going to throw up and then we started asking her the questions that we thought she would answer. did she overdose at a party? i remember her face got really red. she glanced at us and said, we stabbed her. >> it wasn't an accident. it was a murder. and not only had rachel and sheila killed skylar. they had planned it for months. all the while looking and acting like best friends. as sheila and skylar do in this video. as part of the plan, rachel and sheila settled on the night of july 5th as the ideal time to kill skylar. >> earlier that day, rachel had obtained the shovel from her father's residence, put it in sheila's trunk, brought the clean clothes, cleaning supplies and according to rachel, sheila had provided the kitchen knives. >> they called skylar to say they were on their way over. >> pulled up to the residence. >> and there is skylar, sneaking out in that grainy surveillance video. the car is sheila's and inside are skylar's two best friends. >> skylar gets in the car and they go driving. >> and they drove for nearly an hour for miles and miles, dark, winding roads out past blacksville. >> they get to the scene. they parked the car. and they found an area where they could sit and talk. skylar leaves to go back to the car and then rachel said, on three. >> according to gaskins, rachel said she counted, one, two, three. and on three the two girls began. >> that's when her and sheila started stabbing skylar from behind. >> gaskins said skylar fought hard to defend herself. >> did rachel indicate what skylar's last words were, her final moments in that meeting? >> she said skylar just said why? that's all she said. >> rachel said the girls covered the body with dirt and branches, threw their bloody clothes in the trunk and left skylar there. >> did rachel express how she felt when the crime was over? >> i just remember her saying that this is something she wanted to get done before she went to church camp. >> how did you feel when she said, i had to get this done before church camp? >> what are we dealing with? >> did you ask rachel why? why did you two do this? >> she would not give us any specific details other than they just didn't like her. then when i asked her, what do you mean you didn't like her? clarify that. she said, oh, nothing. we just didn't like her. >> after telling police the story, rachel led authorities down that lonely road past blacksville to a spot just across the pennsylvania border. there they eventually found a few scattered human remains and sent them to a lab for testing. >> i just couldn't imagine the pain and suffering and the fear she went through being alone in that place with her two best friends. and she knew what was happening when they started stabbing her. >> authorities kept rachel's confession secret even from the neeses while the investigation continued. the fbi told mary and dave only that remains believed to be skylar's had been found. >> i broke down pretty bad, yeah. >> we both did. that was a bad day. >> it was so lonely and so deserted. and it was a horrible thing to know that she had been there and no one knew. >> one, two, three, go! happy birthday, skylar! >> in february of 2013, just as they had since she was a little girl -- >> i'm ready. >> -- the neeses gathered with friends on skylar's birthday. this time without her. they quietly told the lawrences their awful news. >> did your heart just break for mary and dave? >> my heart was slowly breaking the entire time. >> i remember the first thing i felt it was just like a surreal of, i know she's not out there in the cold. >> ronnie gaskins had a confession from rachel and she had led him to a body. but it wasn't enough. >> why wouldn't you arrest somebody right away who confessed to killing somebody? >> she lied to us a number of times before. who's to say she isn't lying again? we had to corroborate her statement. >> once more, gaskins needed rachel so he didn't arrest her. instead, he was about to use rachel to get sheila. coming up -- >> i was devastated. it was crazy. >> i was crying. she was crying. >> grieving or pretending? >> sheila seemed like she was so upset to have lost her best friend. she even asked me how could someone do this to skylar? >> would the truth catch up to sheila eddy when "dateline" continues. so what's going on? i'm a talking dog. the other issue. oh...i'm scratching like crazy. you've got some allergic itch with skin inflammation. apoquel can work on that itch in as little as 4 hours, whether it's a new or chronic problem. and apoquel's treated over 8 million dogs. nice. and...the talking dog thing? 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why would somebody do this with skylar? >> shania also cried with her friend chrissy swanson. >> once the body was found, sheila seemed like she was so upset she had lost her best friend. she couldn't believe something like this could happen. she even asked me, how could someone do this to skylar? >> and sheila let everybody know how sad she was. she tweeted things like, worst day of my whole life. the pain is real. and rest easy, skylar. you'll always be my best friend. i miss you more than you could ever know. but social media revealed two sides to sheila. she could mourn skylar but on twitter and facebook, she and rachel also seemed carefree. as the police continued their rachel tweeted, i need a mimosa or ten. they were going about their lives even while the police believed the girls were stone-cold killers. >> locals would whisper in each other's ears and say, how are they still free? >> coalbart aroma runs a blog calls newsball.com. early on he started following this case and was struck by sheila's tweets. things like ain't no rest for the wicked. and incredibly this apparent reference to the countdown to skylar's murder. we really did go on three. >> it's unbelievable that she feels she's so invincible to tweet this publicly. >> and then finally by mid-april 2013 ronny gaskins got the one critical piece of evidence he needed. confirmation that skylar's blood had been found in sheila's trunk. >> on top of the video surveillance, the phone records, rachel's statements at that point we felt we had confidence to have probable cause to make the arrest. >> now authorities told skylar's parents the whole story. their daughter's two best friends had killed her. >> i think about it every day. i think about the misery my child must have been through. and i'm helpless. i can't help her. she's calling out "help me, why, why, why." >> animals got her. they didn't even care. >> no. they just threw her out like a bag of trash. >> on may 1st, 2013, in exchange for her cooperation with police, rachel shoaf pleaded guilty to second-degree murder. within minutes, gaskins raced across morgantown, his heart pounding. >> obviously we were going lights and sirens because we had a murder warrant to serve. >> sheila was arrested and charged with first-degree murder in the parking lot of the local cracker barrel restaurant where she and her mom were having lunch. >> sheila was crying. she kept asking her mother, is everything going to be okay? and her mother said, i don't know, sheila. >> gaskins had promised skylar's parents he wouldn't quit until the case was solved. >> it felt good for once that she was coming with us. >> the question of who had been answered. but people were haunted by an unanswered question, skylar's last word. why? the girls had their day in court. but what will they say? coming up -- >> i became caught up in something that i did not want to do. >> the accused killers head to court and the motive for murder? >> they planned that crime for days, weeks, months. >> what could that be? when "dateline" continues. ine. now we've created a brand new way for you to sell your car. whether it's a year old or a few years old, we want to buy your car. so go to carvana and enter your license plate, answer a few questions, and our techno-wizardry calculates your car's value and gives you a real offer in seconds. when you're ready, we'll come to you, pay you on the spot, and pick up your car. that's it. so ditch the old way of selling your car, and say hello to the new way-- at carvana. faced the competition and we broke through. olay's retinol24 complex hydrates better than the $100 retinol cream. visibly smoother brighter skin in just 24 hours. olay retinol24. it's very common to havehave sensitivity a gum health concern as well. you know, i talk to dentists every day and they're able to recommend new sensodyne sensitivity & gum. it's really good dentistry to be able to recommend one product that can address two conditions. hold on one second... sure. okay... okay! safe drivers save 40%!!! guys! guys! check it out. safe drivers save 40%!!! safe drivers save 40%! safe drivers save 40%!!! that's safe drivers save 40%. it is, that's safe drivers save 40%. - he's right there. - it's him! he's here. he's right here. - hi! - hi. hey! - that's totally him. - it's him! that's totally the guy. safe drivers do save 40%. click or call for a quote today. . welcome back. skylar's best friend rachel pleaded guilty to killing her, and prosecutors were busy building their case against skylar's other best friend, sheila. but in a killing that seems so senseless, there was one question that hung over everything. why? here is andrea canning with a conclusion of "something wicked." >> sheila eddy was not about to give in without a fight. there she was in september 2013, a lone black teen in a crowd of accused men, pleading not guilty to the kidnapping and murder of skylar neese. this was terrible news for skylar's parents. >> i didn't want to go through a trial and hear the grisly details of all this. that would tear me apart. >> reporter: with a trial looming, the question on everyone's mind was why. investigators wanted to know, too. in the halls of university high, they got glimpses of a motive, saw snapshots of a troubled, three-way friendship. megan lauren saw a disturbing dynamic firsthand. >> i was not a huge fan of rachel and sheila. >> reporter: as far as back as freshman year, morgan worried that her friend skylar was headed into a place she did not belong when she became friends with morgan and sheila. >> she hung out with the wrong crowd. she had friends that were 20-some years old. that was just kind of strange. >> reporter: morgan watched as the three friends became inseparable. her friend was uneasy, too. >> you would always see them together. >> reporter: in the following year, he saw changes in skylar. >> it seemed like about that time, she didn't have that same nice quality to her. >> she was more sour, i think, toward people. she started almost acting the way that sheila acted. >> it must have been hard to see her changing. >> it's difficult to watch it in general, and it's even harder when it's someone as close as -- someone that you called your family. >> students told riders jeff fuller and daylene barry that by the end of the sophomore year, the three girls' friendships had gun to deteriorate. >> sheila and rachel began dissing her when people were around. >> her friend recalls a chilling conversation. >> she said, i wouldn't mind if she died at this point. >> which makes this cell phone video all the more haunting, because it was caught by skylar six months before she was killed. sheila asked skylar and rachel to choose the best way to die. >> would you guys rather suffocate or get shot? >> suffocate. >> shot. >> would you rather in the head? >> shot. >> drowning or sufficieocating. >> suffocating. it's almost the same thing. >> an incredibly disturbing scene. in the month before skylar's death, she and sheila fought constantly. on july 25th, skylar tweeted this. you doing blank like that is why i'll never completely trust you. later that night, skylar is seen on that surveillance tape driving away from home for the last time. what were they fighting about? there is a possible answer. hallway whispers that rachel and sheila had developed a sexual relationship and that skylar knew and threatened to out them. did they kill her to keep their secret? it's as close to a motive as anyone can come up with. >> do you think we'll ever know why this happened? >> i think it's something for rachel and sheila to say. they know the answers to that. >> in january 2014, david merry finally got the news they had been hoping for. a plea deal. >> sheila eddy, how do you plea to the defense of murder in the first degree of felony charged in count 3 in the indictment in this case? >> guilty. >> sheila's attorney michael bettinger read a statement from his client and their family. >> the family is in a constant state of despair, loneliness and sadness as a result of skylar's death. >> sheila was sentenced to life in prison and is eligible for parole in 2028. a month later, dave and mary went back to court, this time for rachel shoaf's sentencing. >> rachel has a profound sadness at this loss and a profound sadness for mr. and mrs. neese. >> she was hired by the family and has been meeting with rachel since 2013. >> from the day i saw rachel, she said, i deserve to be in here. i did something terribly wrong. i hurt somebody. rachel does miss skylar very much so, and she also weeps for her because she knows she cannot undo the past and that she will never see her again. >> in court, rachel apologized directly to dave and mary. >> i don't know if there is a proper way to make this apology because there is no way to describe the guilt and remorse for something i have done. i got scared and caught up in something i did not want to do. i didn't realize the gravity of my reactions. >> skylar's father did not mince words. >> she murdered my daughter in cold blood. she can take her apologies and sit on them because that's what they're worth for me and my wife. she's done nothing but make our lives a living hell since day one. >> what is your biggest regret if you have one? >> not knowing the girls better. and i don't know if anyone could have known them that well, but there had to be a sign somewhere. there had to be a clue. >> rachel shoaf, would you please stand? >> rachel was sentenced to 30 years in prison. she will be eligible for parole in 2023. dave and mary said don't be fooled by the girls' appearance. >> they planned that crime not just for hours, but days, weeks, months. the horror of that really is what strikes us in the end. not how those girls look in shackles. >> young, whole, attractive, unattractive, male, female, it doesn't matter. evil comes in all shapes and sizes. >> around morgue deamorgantown, lasting damage. teenagers who will never trust each other again. >> after i learned that, i didn't want to become friends with anyone else. >> it's like finding out your little sister is a murderer. >> skylar's friend, morgan lawrence, said she thinks about all the milestones she and skylar planned to map together. >> you two should be doing everything beside each other. >> they didn't just take away a bride, they took away a bridesmaid. >> skylar's parents said they'll miss out, too. >> when morgan walks down the aisle, skylar won't be there. >> she will be. >> she'll be watching over? >> she will. >> in june 2013, dave and mary had a memorial service at the site where skylar was killed. ask they're proud to have helped pass skylar's law, which requires amber alerts even when police suspect a teen has run away. a national version of skylar's law is currently making its way through congress. it's peaceful here now. they come here often, even in the winter, to tend the small garden they've built for skylar. >> mary, how do you want skylar to be remembered? >> the happy, loving little girl that she was. >> and that smile could light up a room. >> that's all for this edition of "dateline." i'm natalie morales. thanks for watching. for watchi. first up on msnbc, at odds. the battle over funding for covid-19 testing and tracing. new reporting today on why the white house is opposing new funds for both. the deepening crisis now one of the best ways to treat coronavirus is in short supply in places of desperate need, while new treatment may be on its way. remembering john lewis. how supporters hope he will be honored in the coming days, and the one thing that might prevent it. and oh, the shade of it all. mary trump dished some family tea this week and now she's throwing some shade at her uncle, speaking his o