catch us again next week for another edition of "what would you do?" you can connect with us anytime. like us on facebook and follow us on twitter. and don't go away. "20/20" starts right now. the parents besides themselves. their daughter is gone. it's evil. >> tonight on "20/20," unfriended. a girl, a mysterious drive in the middle of the night. she didn't come back. does this creepy game by b.f.f.s recorded on a cell phone hold an answer? tonight, "20/20" taking you inside a jaw-dropping mystery. and the secret world of mean girls gone wild.

>> give me the phone. no, this is over. hurry up. >> from twisted messages on facebook, what happens when three is a crowd and one person gets cast aside? what secrets do they have? and who do you believe when pretty little liars seem to be everywhere? tonight, what can happen when you get unfriended? here now, david muir and elizabeth vargas. >> good evening. your teenagers could be planning it right now. sneaking out of your house, joyrijo joyriding around town. but this would be just the start of a mystery that devastated a

community. what did this ominous tweet, #what if i could get away with it, mean? >> the texts and tweets and facebook fights between b.f.f.s. where getting unfriended is just the beginning. here's ryan smith. >> reporter: they were 16 and inseparable. best friends, high school sophomores shelia, skylar and rachel. >> it was always those three together. >> you barely ever saw one of them by themselves. >> reporter: silly in their selfies. >> giggly teenage girls. >> they're pretty, they're sociable, they're popular. >> reporter: but behind their smiles, secrets that would shock everyone they knew. >> the level of deception, it's mind-boggling. >> the police were just as shocked as we were. >> no one was expecting anything like that. >> pure evil. >> reporter: nestled in the green mountains of west

virginia, the city of morgantown, home to west virginia university, known as a friendly family place. what's it like here in morgantown? >> it's peaceful, it's a small town that's growing really fast. nice people. >> reporter: dave and mary neese live in an apartment in the tiny morgantown suburb star city. dave works at a local walmart, mary at a medical office. their lives wrapped around their only child, skylar. >> hey, gorgeous. >> hi, daddy. >> reporter: treasuring every spin, every laugh, and every childhood memory. >> i think it was the time she had the tea party for me, and after mary came home, she noted that skylar couldn't reach the faucet and i'd been drinking toilet water for the whole tea party. that was a good memory. >> at the time it wasn't a good memory. >> my crazy girl.

>> reporter: she was daddy's little girl. >> i spoiled her beyond rotten. she was very loyal to her friends, the people she thought was her friends. >> reporter: when skylar was eight years old she met another spirited child with whom she developed an instant bond. her name was shelia eddy, and they became thick as thieves. >> if they weren't together, they were on the phone together. and that's literally 24 hours a day. i'm serious. it was always, you saw one of them, you saw the other one. >> reporter: what was your relationship like with shelia? >> she was like a part of our family, she really was. i mean, just like one of our kids. >> reporter: as a teenager, skylar had a 4.0 gpa, a part-time job at wendy's, and an active social life. in their freshman year at university high school, skylar and shelia meet the striking redhead rachel shoaf.

the duo becomes a trio. kelly kerns was close to rachel. >> she called me her cool aunt. >> she was like a daughter to you. >> yes. >> reporter: kelly says rachel was charismatic, popular, and talented, cast as the lead in the school play. >> what was she like on stage? >> she was a natural. >> reporter: on rachel's 15th birthday, rachel introduced kelly to her new best friends shelia and skylar. here they are that night. >> they were two adorable little girls smiling up at me, you know, just looking so angelic. >> reporter: but that vision of angels would soon be shattered. july 5th, 2012, skylar finishes a night shift at wendy's. >> skylar walked through the door, gave her mom a hug, and said, "i love you, mom." then she hugged me and said, "i love you, dad." she went to bed. >> reporter: the next day dave and mary go to work. but when he returns home that afternoon, skylar's bedroom door is still closed. >> i knocked on her door. there was no answer. so i said, "sky, come on! you got to get up."

and i still didn't get an answer. so i opened the door, and i looked down at her bed and it hadn't been slept in. and it scared me. so, i immediately called mary. she said, "she's not home?" and i said, "no." >> reporter: concerned, his next call -- shelia. >> she answered on her first ring. and i said, "you got any clue where skylar is?" she said, "no." i said, "when's the last time you talked to her?" she said, "last night about midnight." >> reporter: looking for clues in skylar's bedroom, dave discovers something out of place. when you came in here that day, describe what this looked like. >> the screen was gone completely, and i found it in her closet. and the window was open about that much so she can get her fingers and lift it back up. i found a bench right here. >> reporter: outside the house dave points out where he saw a bench, a way for skylar to climb back into her bedroom. >> then i knew. oh my god, she snuck out last night and she's not home. now i started freakin'. >> reporter: it's now 4:00 p.m. and it's time for skylar's next shift at wendy's.

skylar had never missed work, but today she's a no-show. >> wendy's called and said, "hey, is skylar coming to work today?" and i said, "aw, jesus." and mary said, "call 911." >> 911, do you have an emergency? >> i have a 16-year-old daughter, can't get a hold of her, and i'm scared to death. >> has she done this before? >> no. >> reporter: just then, mary gets a phone call from shelia. what did she say? >> her words were, "i have to tell you the truth about what happened last night." she proceeded to tell me that her, skylar, and rachel had snuck out the night before, and that they had driven around star city. were getting high, and that the two girls had dropped her off at the end of the road. because she didn't want to wake us up sneaking back in.

>> i was scared to death. i mean, i didn't know where my baby was. it was horrible. >> reporter: shelia and her mother come over and offer to help search for skylar. >> we immediately went looking for her, going door to door. and we just, we couldn't find her. >> reporter: but then mary remembers what will become a major key to finding skylar's whereabouts. >> mary said, "oh, what about the surveillance?" we got surveillance at our apartment. >> reporter: the surveillance camera, intended to capture intruders, instead reveals this grainy image of that night. a car pulls up at 12:30 a.m., 30 minutes after shelia says she dropped skylar back near home. skylar is seen sneaking out of the house she slips into the car and disappears. what were you thinking when you saw her head flash on that screen and she's walking to that vehicle? >> for a second i felt relief 'cause at least i know she didn't get abducted or anything. >> and it wasn't like she was pushed in. she willingly got in the car. >> reporter: what did police tell you that they thought happened?

>> they thought that shelia had dropped her off and skylar came back home, and then snuck out again. >> reporter: for officer jessica colebank and corporal ronnie gaskins, the video is their best and only clue. what were you looking for? >> anything. >> trying to get pictures of the tires, the rims, but it's just too grainy. >> it just raised millions of other questions, of who did she go with and where did she go? >> reporter: next, what happened to skylar? everyone has their own theory. >> got drunk and fell and hit her head. >> somebody had followed her home. >> she'd met someone on the internet. >> somebody's just too scared to tell us what really happened. >> reporter: stay with us. ♪ ♪ [ male announcer ] if you can't stand the heat, get off the test track. get the mercedes-benz you've been burning for at the summer event, going on now at your authorized mercedes-benz dealer.

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"20/20"'s unfriended continues. once again, ryan smith. >> reporter: this is the last sighting of 16-year-old skylar neese. surveillance video outside her home in west virginia. an eerie vision as she sneaks out of her bedroom, enters an unknown car and vanishes. >> video from the apartment

shows the 16-year-old willingly leaving the apartment. >> reporter: she seems to have left her home voluntarily, so police do not activate an amber alert. officer jessica colebank is assigned to the case two days after skylar's disappearance. did you think it was a runaway case at that point? >> it does happen. kids run away. they come home a couple days later, parents find them. >> reporter: skylar's parents dave and mary are frantic. dave pleads on local tv for help, begging his daughter to come home. >> we love you. come home as soon as you can, baby. honey, if you are scared, don't be scared. you're not in trouble. we need to talk and that's all. just come home. >> reporter: each time they get calls with possible skylar sightings they rush into action. >> i'd jump in my car and fly to the place they thought they saw skylar. i'd go down to the supermarket and scream her name. i mean, everywhere they thought they saw skylar, we were there. >> reporter: skylar's friends

were worried but hopeful. morgan lawrence has known skylar since they were 3 years old. >> i thought that maybe there was a fight, maybe there was something that made her upset, and that she'd be, you know, she'd be back the next day. >> i thought maybe she just, something happened at home, she wanted to get away. >> reporter: amorette hughes, another friend, writes skylar messages on facebook pleading with her to come home. >> hi beautiful, i love you, and i miss you, come home soon. >> reporter: the inseparable trio of skylar, rachel and sheila is now missing a key member. as for rachel, just hours after skylar's disappearance she's happily posing for pictures on a boat with her family friend kelly kerns. but kelly says rachel is worried about her missing friend. >> i mean, she was texting all the time. she seemed urgent. >> reporter: meanwhile her other best friend, shelia, is in constant contact with skylar's parents, helping them post missing person posters. tweeting messages like this, was

really waiting for skylar to come home. just days after skylar's disappearance, shelia comes to the neese's home, devastated, with a special request. >> she says, "is it okay if i go back and sit in skylar's room for a minute? for a few minutes." >> she was crying, shelia was. crying pretty hard. and she was sitting on her bed, so i just sat down on the bed beside her and rubbed her back. i was trying to, you know, console her, make her feel better. >> she was going through the same thing we were going through, just at a smaller level, you know. i mean, this is our baby that's gone. we're flipping out. her best friend is gone. it's horrible. >> reporter: days turn into weeks, and still no sign of skylar. no activity on her cell phone or bank card, and her parents doubting the runaway theory. >> she didn't take her cell phone charger. she didn't take her contact lens solution. >> apparently she was planning to come back fairly quickly. >> reporter: in tight-knit morgantown, people are searching

for skylar and wondering what could have happened to her, like local crime writers geoff fuller and daleen berry. >> there were lots and lots of rumors floating around. she got drunk and fell and hit her head. >> somebody followed her home. >> she'd met someone on the internet. >> reporter: and then a possible break in the case, two bank robberies in nearby blacksville. corporal ronnie gaskins hears rumors that money from the robberies was used to buy drugs for a local teen party. >> skylar had supposedly overdosed on heroin. she died. people there panicked and they disposed of the body. >> reporter: where did that lead take you? >> we weren't coming up with anything. >> reporter: shelia and rachel, the last two people to see skylar, have nothing to add to their story. they picked up skylar at 11:00 p.m. took a joyride through the winding backroads of rural star city, smoked pot, then dropped her off before midnight. >> very often, the last person to see the victim alive is looked at with great suspicion. in this case, the girl's story

seemed relatively innocent. so police had no reason to believe both of them were lying. >> reporter: but for officer colebank it's the small, unspoken signs that make her suspicious. take me back to that moment where you go to speak to sheila the first time. >> just complete blank on emotions, and there was absolutely nothing. it was, like, iced over. it made me uneasy. >> reporter: colebank's meeting with rachel, the high school drama star, also strikes her as odd. >> she was really nervous. >> reporter: which has got to be a red flag. what does she have to hide? >> their stories were verbatim the same. no one's story is exactly the same, unless it's rehearsed. and she's an actress, so she can memorize lines. i'm sure they had it written down somewhere. okay, this is our story, we've got to stick to it. everything in my gut was sheila is acting wrong. rachel is scared to death. >> reporter: but police don't know what rachel and sheila are

hiding, or why. meanwhile, skylar's parents are grasping for any clues, taking a closer look at the bad influence shelia had become on their daughter. >> sneaking out at night, you know. found some marijuana in skylar's pocket one time. heard it was shelia's. >> we didn't like the way shelia acted a lot of times. but she was skylar's best friend. we kind of overlooked it. >> reporter: it's becoming clear that the smiling face of skylar's b.f.f. was just a facade. you started interviewing people about shelia. how would they describe her? what was she like? >> shady, sketchy, sneaky, and pretty manipulative. >> reporter: skylar's friend morgan says shelia rubbed her the wrong way. >> she was very self-centered. she would almost do whatever it took to kind of get her way. >> reporter: amorette says skylar confided in her, that there were cracks in the clique. her best friends were snubbing skylar. these pictures that shelia posted on the website meet me

suggest skylar has become a third wheel. >> she just thought that they were becoming closer, so they were just pushing her out. she was really upset about it. >> reporter: the slights were sometimes subtle, but clear as day for skylar. >> they would dress the same, they'd both wear dresses, or skirts, but they wouldn't tell skylar, and they would say it was more like a coincidence. but i secretly think that they planned it. >> reporter: are shelia and rachel hiding a secret about what happened to their best friend? officer colebank is determined to find answers to bring the neeses' daughter home. >> i promised dave and mary the very first day that i met them, i said, i'm a bulldog in my investigations. i said i don't care if it takes me ten years to find the truth, i will eventually find it. >> reporter: next -- the girls play a strange secret game captured on camera by skylar. >> drowning or suffocating? >> where would it lead?

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"20/20" continues with unfriended. here again, ryan smith. >> reporter: police have begun to suspect that shelia and rachel, best friends of missing 16-year-old skylar neese are lying about what happened the night she vanished. the first red flag -- tension in the relationship. officer jessica colebank pores through skylar's old facebook and twitter posts. what she finds sets off alarms. >> you could tell she was mad at someone. >> reporter: in the weeks before

she vanished, skylar had posted angry messages. "there's just something about you i can't stand." "people can be so mean for absolutely no reason." "hope you don't expect me to give a [ bleep ] anymore. #bye." and the final tweet she wrote, sent 10:48 p.m. the night she disappeared, "you doing [ bleep ] like that is why i will never completely trust you." >> she didn't trust someone, that was the issue. >> reporter: and perhaps the most suspicious posting by skylar, this strange game among best friends. shelia asks rachel and skylar how they prefer to die. >> would you guys rather suffocate or get shot? >> get shot. shot. >> drowning or suffocating? >> suffocating. >> it's almost the same thing. >> i know but it's not. >> reporter: and when police review rachel and shelia's cell phone messages after skyler went missing, they note a curious absence. >> there was no mention of skylar whatsoever. it was very odd. it's as if she just erased it

from her, from her mind forever. >> reporter: skylar has been missing for months, despite her parents concerns about shelia's bad influence, they're convinced that shelia is simply grieving over her lost best friend. even as the police are saying to you they've got some suspicions about shelia, you were thinking, hey, back off of this girl. >> oh, i even told them. i said, "will you please leave her alone? she's going through enough." i said, "those girls have just lost their best friend. will you chill out on her for a while?" >> reporter: what the neeses don't know is that police are finding actual evidence of the girls' deception. shelia and rachel told police their joyride with skylar was contained to the star city area. desperate for clues, police scoured surveillance video from local businesses. it paid off. this video captures shelia's car at 12:39 a.m. heading north, away from star city. >> that was the first variation in their stories, is where they drove around. >> reporter: and there's not just video.

cell tower pings from that night place them in the backwoods town of blacksville. >> that just blew their whole, oh, we stayed in star city. you're 45 minutes away from where you're saying you're at. you can't do that. you're not houdini. >> reporter: so, you say, aha, we have this information. what happens when you speak to rachel and sheila? >> they change their story to fit, oh sure, we were in blacksville, i forgot that. oops. >> reporter: the carefully rehearsed stories are now mismatched. shelia, the high school drama queen, claims skylar didn't join them for the ride to blacksville. but rachel, the high school drama star, says she did. they're starting to differ, at least from rachel's perspective, it sounds like the actress is starting to forget her lines. >> oh, yeah. she had to come up with her own

line and that's where she really started tripping up. >> and once you start seeing inconsistencies in a story, it's all over. the person's lying. and then you must ask the question, why would they lie? >> reporter: shelia is adamant that her version of the night's events is true. she volunteered to take a polygraph. what did that say to you? >> arrogance. i think she thought she was smart enough to outsmart a machine. >> reporter: so, she took the polygraph, and what happened? >> failed miserably. >> reporter: rachel also agrees to take a polygraph. but en route on the day of test, she gets scared, jumps out of her father's car and flees. >> she jumped out of a moving vehicle to avoid it. if you haven't done anything wrong, why won't you take this test? >> reporter: now, armed with surveillance video and cell phone records that prove the girls have been lying, police tell dave and mary neese that skylar's best friends have a secret. >> at that point we knew they had to know something. so we pushed. >> reporter: your mission is to try to get their secrets out of them. >> exactly. >> reporter: the neeses start posting about karma on facebook, writing that the girls need to tell what they know. classmates and even strangers

are putting pressure on shelia and rachel. anonymous tweets like this one -- "pretty little liars keep on lying!" >> all eyes were on sheila and rachel. you know, you can't be part of the trio and not have any clue what's going on. >> reporter: kelly kerns, close friends with rachel and her mother, hears the rumors that rachel is stonewalling police. >> i'd get a text from people, why isn't your friend's daughter cooperating, so i'd send rachel a text. what the heck are you doing? >> reporter: even those closest to rachel are wondering, what is she hiding? >> i said, was skylar alive when you left her? yes. we didn't do anything to her. >> i think that in this situation, you cannot lessen the importance of peer pressure. >> reporter: rachel seems particularly affected. as the lead in that year's school play, she is accustomed to adulation. >> it's like she was getting

booed in a performance. it's that type of level of ostracizing her. she couldn't handle that. >> reporter: one night, almost six months after skylar went missing rachel cracks, apparently having a nervous breakdown. her mother calls 911. >> i have an issue with a 16-year-old daughter of mine. >> no, this is over! >> hurry up. >> oh, god. hurry up, please. >> reporter: seemingly suicidal, rachel is admitted into a local psychiatric hospital. what happens there has never been revealed, but immediately upon release rachel is driven directly to meet with police. >> she was just nervous, she was shaking. it was like, now the truth's finally gonna come out. >> reporter: next -- you'll never believe what rachel tells police. this was something totally different from what you expected. >> it just struck me as unbelievable. >> it just struck me as unbelievable. >> there was n♪ ccident. glade scke the most beautiful feelings.

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"20/20"'s unfriended continues. once again, ryan smith. >> reporter: university high's leading lady rachel shoaf is not able to keep up the act any more. six months after the disappearance of skylar neese rachel's abandoning the role of heartbroken best friend and going from a psych ward straight into the interrogation hot seat. >> she was just nervous, she was shaking. >> reporter: she's finally about to come clean to police about what really happened to her 16-year-old b.f.f. it's plot twist no one saw coming. >> the first words out of her mouth were, we stabbed her. >> reporter: this was something totally different from what you

expected. of settle down. okay, "what do you mean, you stabbed her?" >> reporter: rachel tells corporal ronnie gaskins she and shelia began plotting to kill skylar months earlier during science class. >> they were joking how they would dispose of a body. then it got more sinister, we need to figure out how we're going to kill her. they don't know to use guns, so they would use knives to stab her. >> reporter: rachel wanted skylar dead now because, get this, she was about to leave for church camp. so one midsummer's night she and sheila gather some critical tools. a shovel, paper towels, bleach, wipes, a change of clothes and kitchen knives. they arrange to meet with skylar. remember this grainy surveillance video? police couldn't make out the car. turns out it had been shelia's all along. 12:30 a.m., they arrive at skylar's house. the knives hidden in their hoodies.

five minutes later, skylar emerges. they drive out of star city, past blacksville and across state lines to pennsylvania and into the woods of a town called brave where skylar is about to face the fight of her young life. they are driving on this road that we're on right now and skylar is in the back seat having no idea what's about to happen? >> she has no clue. >> reporter: gaskins takes me back to the murder scene. man, this is dark and creepy. >> just imagine, these girls are out here after midnight. >> reporter: and recounts what rachel confessed. >> all three girls exit the car. and they walk down this road. >> reporter: the girls find a grassy area to sit and smoke marijuana. skylar gets up and starts walking back to the car to get a lighter. that's when they execute their secret plan. sheila and rachel get up behind her and count -- one, two, three. >> and on three, that was the time for them to start stabbing skylar. >> reporter: right here? skylar is being stabbed by her two best friends? >> yes.

>> reporter: skylar takes off running with her two friends giving chase. rachel tackles skylar and the pair continue to repeatedly stab their b.f.f. >> according to rachel, skylar is screaming "why?" >> and then they tried slitting her throat because they had read that it would kill her quicker if they cut her jugular. >> reporter: the plan was to bury her but the ground was too hard, so instead they drag her body to the side of the road and cover her with branches, rocks and leaves. they don't even bother to really conceal her. >> they change into clean clothes, they wipe down the car and they left. like nothing happened. >> this was calculated, planned out, thoroughly thought of before this night. >> reporter: the perfect murder plot, everything planned to the "t." but why? >> her only answer to that was, we just didn't like her. what do you mean, you just didn't like her? we just didn't like her. well, why not?

>> reporter: did you ever get the sense with rachel that she really remorseful about what she did? >> she seemed to be relieved that the truth has been told, she doesn't have to hold it in anymore, it's not eating at her anymore. >> reporter: shockingly, even though rachel confessed, gaskins doesn't arrest her. >> we had no body, we had no physical evidence. i mean, we had all this circumstantial evidence. but we needed something more concrete. >> reporter: and there had been no cracks in sheila's armor. so to try and nail her that night, police put a wire on her friend rachel, hoping sheila incriminates herself. but sheila doesn't take the bait. instead, the two killers take this smiling selfie together. sheila tweeting, finally got to see rach. then a break, police think they have an ace in the hole linking sheila to the murder. they find traces of blood in her car. >> we had to do a dna confirmation. >> reporter: meanwhile, rachel continues to give critical details to police. details skylar neese's parents so desperately await, like the

location of skylar neese's body. >> and this area right here is where we're able to finally locate, skylar's remains. >> reporter: she was one, two, three, four, five, six, maybe seven steps away from the road? back in star city the neese family is holding a vigil on what would have been skylar's 17th birthday. they are finally told the news they've been dreading. skylar had been murdered. >> i was outraged. i was a mess. all these emotions running through my head at once. >> the search is over. >> she was our world, and now she's not here. >> reporter: the identities of the killers was not revealed. and immediately sheila eddy takes to twitter to join the chorus of grief. "worst day of my life."

"the pain is real." and "rest easy skyler you will always be my best friend." at the same time she is pretending to mourn online sheila is brazenly taunting police. tweeting messages like "wonder if there's a law and order svu where they don't figure it out." and "we really did go on three" a seemingly blatant reference to the crime. but what sheila doesn't know is that authorities get their biggest break yet, conclusive evidence linking her to the murder. a dna match confirms that blood from the trunk of sheila's car is skylar's. it's that final piece that really nails sheila. >> and that news that i was waiting to her. >> reporter: finally with enough evidence to arrest sheila, gaskins closes in and tracks her to the cracker barrel where she is having breakfast with her mother. >> i just want to be able to get her right then and there. >> reporter: it's a race against time at this point. >> we're not just dealing with a 16-year-old girl. this is a cold-blooded murderer. >> reporter: it's the end of road for sheila. she is leaving the cracker barrel just as gaskins pulls up, cuffing the teen killer right

there in the parking lot. >> i advised them, she was being charged with the murder of skylar neese. >> reporter: also a huge victory for that young cop who wouldn't quit, jessica colebank. >> elation. pure joy. >> reporter: and what did you say when you brought her to jail? >> home sweet home. and then we shut the door, with a big old grin on my face. >> reporter: case closed for colebank, but for skylar's parents dave and mary, learning the killers' identities not only brought more heartache and devastation but also fury. >> they're acting like they really care and they're the ones that are responsible for the whole thing the whole time. >> reporter: casting devastating new light on that moment when sheila was overcome with emotion in skylar's bedroom. >> oh, my lord, we believed that garbage. >> can you imagine? your daughter's killer, sitting on your daughter's bed, crying. and the mother, putting her arms around her daughter's killer.

>> skylar trusted those two little witches and it cost her her life. best friends like that, you don't want any enemies. for sure. >> how could they do that to their best friend? >> reporter: and the reason rachel gave -- that they just didn't like her? >> that's the biggest line of crap i've ever heard in my life. there has to be a reason. you don't do stuff like that for no reason. >> reporter: when we come back, the real motive. was skylar hiding something about her friends? did she know too much? >> skylar knew stuff about them that they didn't want out. >> reporter: her secret diary that they didn't want out. >> reporter: her secret diary revealed. (whispering) (whispering) hi, uh we need a new family plan. (whispering) how about 10 gigs f data to share and unlimited talk and text. (whispering) oh ten gigs sounds pretty good. (whispering) yeah really good. (whispering) and for a family of four, it's $160 a month (impressed, breaks whisper mode) what! get outta here! (whispering) i'm sorry are we still doing the whisper thing? or? (whispering) o! sorry! yes yes! we'll take it. at&t introduces our best-ever family pricing. for instance, a family of four gets 10 gigs of data,

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unfriended. here again, ryan smith. >> reporter: she's a killer nobody would have suspected, the fresh-faced high school senior, shelia eddy, smirking in her first court appearance. after months of secrecy, the truth is revealed. skylar neese's best friends rachel and shelia were actually her worst enemies. the shocking news they had lured her into the woods and brutally stabbed her to death. >> the search for skylar neese is over. >> rachel confessed. >> two teenagers implicated. >> reporter: many of skylar's friends hear about it at school. >> it devastated me. i actually had to get up and leave class. if you don't want to be friends with anyone anymore, you delete them on facebook, like, you don't go and get rid of them. >> reporter: kelly kerns has known one of the killers, rachel, since the day she was born, considering her like a daughter. >> when someone tried to tell me

that they stabbed them -- i -- no way in heck. >> reporter: you couldn't believe that was your rachel. >> you can't tell me these girls stabbed her. and it wasn't until i opened the paper and saw guilty, and her picture. >> reporter: today, looking at the photograph of rachel taken just hours after she murdered her friend. kelly is floored by that smiling face. what strikes me about this picture is, i don't see anything on her face that reflects what she did. >> it just makes you feel, you know, what did you miss? >> reporter: and at the heart of the wrenching questions, how could two teenagers kill their best friend? >> they say they just didn't like her anymore. which is typical of teens. but teens typically don't kill each other when they fall out of like. >> i think it was because skylar knew stuff about them that they didn't want out. >> reporter: stuff he says was hidden in skylar's diary where he says she wrote about a sexual

relationship between shelia and rachel which she witnessed at a sleepover at rachel's house. they describe the incident in intimate detail in the new book they've written called "pretty little killers." >> shelia and rachel became involved sexually, it appears. skylar was forced to watch, because she knew if she left the bedroom they had all been drinking and they'd all be in trouble. >> reporter: several weeks after the sleepover, skylar tweets "i'd tell the whole school all the [ bleep ] i have on everyone, which is a lot. #ificouldgetawaywithit." then one month before she is murdered there is another tweet from skylar, "just know i know"" >> rachel and sheila had formed some type of a sex relationship that they believed skylar knew about it and would ultimately tell everyone. >> reporter: but the neeses say that skylar never would have acted on the veiled threats. >> she had a lot of gay and lesbian friends. it didn't bother her. you know, she didn't care if you were pink, purple, yellow.

that was just skylar. >> reporter: why do you think they killed her? >> for the thrill of it. to see if they could get away with it. >> they had a strong dislike for skylar. so it's fitting they stabbed her in the back. >> reporter: a year and a half after the murder, rachel faces justice. she pleads guilty to second degree murder, a lesser charge based on her cooperation. finally, in court, she directly addresses the neese family. >> i am so sorry. i don't know if there is a proper way to make this apology because there are not even words to describe the guilt and remorse that i feel each day for what i've done. the person that did that was not the real me. not the person i am, not what i'm made of and not what i believe in. >> reporter: rachel's mom weeps as she listens. >> and i'm so sorry and i pray each day for everyone involved and i pray each day for forgiveness. >> she can take her apologies and everything else and sit on them because that's about what they're worth to me and my wife.

she has done nothing but make our lives a living hell since day one. >> reporter: she was crying, she was emotional. you didn't think that was remorse? >> to me, that was her final act in front of an audience. she's the big actress, the star of the high school plays. this was her last broadway performance. >> reporter: at her arraignment, a defiant shelia eddy pleads not guilty. but later, in a surprise development, changes her plea. >> how do you plead? >> guilty. >> reporter: guilty to first degree murder. she offered no words of remorse. why do you think that shelia has never apologized? >> because she's not sorry. you don't apologize for murdering somebody in cold blood. because she meant to do it. >> it's a good thing she didn't give an apology. people think it's horrible because she didn't. i commend her. don't stand up there and lie to

me and tell me you feel guilty. >> reporter: rachel's family described her actions in a statement as "unforgivable and inexcusable." she is now at a juvenile facility, sentenced to 30 years in prison. she will soon be transferred to adult prison. the same prison, in fact, where the sheila, the girl she turned in, is now serving a life sentence. but both girls could be out on parole by their early 30s. >> if i'm dead and gone, somebody will be there to make sure they talk to the parole board and these animals don't get out of their cages. >> reporter: if you could say anything to shelia and rachel right now, what would you say? >> rot in hell. >> reporter: skylar's friends are still trying to process their loss and mourn the milestones they are experiencing without her. >> skylar never got to go to a prom. mary and dave never got to see her get all dressed up, and get

the bouquet, and get everything else. >> reporter: in memory of their only child, dave and mary neese helped pass skylar's law in west virginia. it requires amber alerts for all missing children. >> this is skylar's room. >> reporter: when you come in here, does it give you any sense of skylar now? >> yeah, it still does. >> reporter: they continue to treasure every item that belonged to skylar. >> some of them don't mean anything, but they were hers, so we'll always keep them. >> reporter: she has a bunch of cards and drawings. >> yeah, see her friends were always sending her "a birthday wish for my friend." uh-oh. that's what i think of that one. >> reporter: yeah. >> that was from shelia, by the way. >> reporter: the card reads "happy birthday, love shelia. bff. love you like a sister for life." for dave, it's just one more reminder of a searing betrayal that has destroyed their world. >> because of that outward appearance, people don't want to believe they're capable. i've still, to this day, have

people say there's no way it's just those two girls. yes. it's those two girls. >> this crime to me is one of those crimes that go down in the books as truly evil, best friends from hell. there couldn't be a more fitting description. >> reporter: today on a hidden road, deep in the woods of a town called brave, there is a silent shrine. the site of skylar's murder has been transformed into a memorial. on this visit, a stranger had written a note to skylar. >> this one says, rest in peace, sweet skylar. soar with the angels. baby, i'm so sorry. if there's one lesson to be learned in here, and one lesson

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the investigation into shot down flight 17. >> as more friends and family of the victims share their stories. abc7 news begins in 60