love by faith. ♪ fay yay yay yay yay ♪ fay yay yay yay yay ♪ we feel the faith [cheers and applause] this is "nightline." >> tonight, the wicked. the 12 year old lured into the woods. >> do you remember leaving the park to go to the woods? >> the brutal act of betrayal, stabbed 19 times and left for de by friends she thought she could trust. >> who's ever heard of two 12 year old girls planning for six months to kill one of their best friends. >> the chilling twist shocking the world five years ago. >> who's slender man? >> he's this tall, faceless man who preys on children. >> now david muir's exclusive interview, the survivor speaking out for the first time about her

scars and the strength she found to face her worst nightmare. "nightline," "the wicked", will be right back.

good evening. thank you for joining us. for one young girl an online horror story became a gruesome

rial. surviving a brutal stab that stunned the world five years ago. it's a case david muir has followed from the very start. the victim now sitting down for an exclusive interview. ♪ >> reporter: do you feel like you're a survivor? >> yeah. i shouldn't be alive. i really shouldn't, after what happened. >> reporter: for the first time, peyton lightner is talking about that day five years ago, three 12 year olds at a slumber party, and the next morning, a walk into the woods to play hide-and-seek. do you remember leaving the park to go to the woods? >> they just wanted to go on a walk, and i didn't think much of it. it's just a walk. what bad stuff happens in walk shaw, wisconsin? >> reporter: peyton was stabbed 19 times and left for dead by her own friends who later blamed the fictional character slender man. >> when i was five feet away, i said now, go ballistic, go

crazy. stab, stab, stab. >> the suspect lured the victim into the woods. all three of the girls are 12 years old. >> who ever heard of 12 year old girls planning for six months to kill one of their best friends. >> through the whole time, peyton was screaming in agony. >> i didn't want to do this. i was pafraid what would happen if i didn't. >> reporter: it's friday night, in wisconsin, a milwaukee suburb. peyton is et goigetting ready t celebrate her best friend's birthday at that slumber party. >> she was so, so, excited. >> reporter: she was a loper neo needed a friend. >> i made friends with her when i saw she didn't have any friends at all. >> reporter: also, anisa, who

had grown close to morgan. >> they played up in morgan's bedroom, ran up and down the stor stairs giggling and laughing&-p. >> reporter: but there was nothing normal about the next morning when they suggested they go to the park and to the woods together. >> anisa told me to lie on the ground and cover myself in sticks and leaves and stuff, but it was really just a trick. >> reporter: while playing hide-and-seek came the command. and she's attacked with a knife. >> she said don't be afraid, i'moi'm only a little kitty cat. and she stabbed her profusely. >> reporter: do you remember when it started? >> kind of. i didn't feel anything. because my body was in shock. they told me to lay down. you'll lose blood slower, like

we're going to go get help. >> did she try to get up? >> yeah, she tried to get up. she said she couldn't see. she couldn't walk. and just that she couldn't breathe. >> and they told her they were going to go get her help. but anisa flat out said we're not getting her help. we wanted her to die. >> i got up and walked until i hit a patch of grass where i could lie down. >> reporter: a bicyclist calls 911, officer dan kline is the first on the scene. >> i asked her who did this, and she told me her friend morgan. >> reporter: peyton tells paramedics she's been stabbed. >> they asked how long is the knife, and she said the knife is about like this. and she was talking about the blade, not the handle. >> reporter: her mother rushes to the hospital just before peyton is taken into surgery. >> i said, you're going to be okay. it's going to be fine. but i could see that she was covered. her arms and her legs and her

abdomen were covered in stab wounds. >> reporter: the surgeon treating peyton told me if the stab width had been a width of a hair deeper she would not have survived. while preyton fights for her lie police are searching everywhere for the two girls. >> it was about 2:53 in the afternoon. i had gotten a message that the sheriff's department had located the girls on the side of i-94. they were sitting on the side of the freeway. >> by the time we had found them, they had walked about five hours and made it to the north end of our city. >> reporter: morgan geyser and anisa were brought back for an interview. >> they seemed kind of meek. >> your parents know you are here talking to me. they're so glad that you're safe. >> i did notice she had a bloodstain on the front of her

shirt and she was wearing two shirts. >> what is your name? >> anissa weir. >> morgan seemed like she was very calm. very relaxed. i mean, she's at a police department, and she's covered in blood. and this is like a normal day for her. >> what's your name? >> morgan. >> reporter: you can hear morgan ask what's happened to peyton, using her nickname, bella. >> is she dead? >> i don't know. she was taken to the hospital. >> what? i was just wondering. >> it didn't seem like it really concerned her too much if she was dead or e. >> reporter: the dectectives red the girls their rights. >> here in the state of wisconsin a child can be

interrogated without the presence of their parent or guardian being in the room. at that time, i did not know that. >> we find people are more truthful when they don't have their parents present. >> this is to get me arrested, isn't it? >> reporter: the interrogations last for hours. >> make yourself a little more comfortable here. >> i have a daughter that's almost the same age as her. like she could be my daughter, but then she started saying things that were really very eerie, even coming out of a 12 year old's mouth. >> did you talk about doing this beforehand? >> anisa told me we had to. >> why? >> because he said that he would kill our family. >> who's he? >> um, a man. i didn't know him. but anisa knew him. >> reporter: and this is where the story takes another turn to a fictional character on the internet. >> what they called, it's

of horror stories that are meant to purposely scare you. one of those called slender man. >> who's slender man? >> he's, he's this tall, faceless man who preys on children. >> at his own will, he can extend these ten drills from his back, and like strangle his victims. he targets childrens most. >> anisa explained to me that to prove yourself worthy to slender you would have to kill somebody. >> morgan said we have to kill bella. >> reporter: when we come back. >> did you feel bad? to stab one of your best friends? >> i thought about it, but then i decided that remorse would get me nowhere. it's easier to live without regrets. assurance of a 165-point certification process. or it isn't. it's either testing an array of advanced safety systems.

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xfinity x1. simple. easy. awesome. xfinity. the future oawesome. "nightline" "the wicked" continues. here again, david muir. >> anissa told me we had to. >> why? >> because she said that he'd kill our families. >> who's he? >> um, a man. i didn't know him. but, anissa knew him. >> reporter: 12 year old morgan geyser and her friend anissa weir are being interrogated for stabbing their friend peyton 19 times. the reason behind their attack they say is a fictional character named slender man. >> who's slender man? >> he's this tall, faceless man

who preys on children. >> he could be anywhere from 6 feet to 14 feet tall. he comfortably wears a suit. he doesn't have a face. his skin ais white. >> it all started online with two photographs and two paragraphs. one showed a group of smiling kids playing with a slender man in the background and another one was a more pensive picture. the story that went with it explained that these were photos that were taken right before a bunch of children had gone missing and that was it. >> it's sort of going down the rabbit hole of the internet. the stories looked real. articles that looked like real news articles. >> we're going to be looking for slender man. >> wait, wait, wait. >> no, no, no. >> i actually thought that he was real. because i saw him. we were, like, talking on the bus. i look out the window, and i see

this thing, sanding like this, with tendrills, looks exactly like a tree. like that. >> as morgan learned more about slender man, it came to dominate her thoughts. and she got closer to anissa and a little more distant from peyton. >> i didn't really understand what we were doing, but i really didn't want to make anissa mad. it's hard enough to make friends. i don't want to lose her over something like this. >> morgan has never hurt a fly. it was just unthinkable that morgan would do anything to hurt someone else. >> i've wanted to hurt people before, but they're not nice to me, so they deserve it. >> do you understand what it means to kill somebody? >> i mean, i've seen stories on the news, but i never really fully understood what it was like to kill somebody until now.

>> bring back. oh, bring back my bonnie to me. >> me. >> anissa was very imaginative. she would always imagine a bigger and better life for her barbie dolls. i don't think she really made friends that easy. >> morgan didn't do a lot of bullying. especially in the sixth grade by the other students. in the last year, she started to become moodier and a little bit more reclusive. >> she never talked about any of the sad nut or any of the bad things. they knew what each other had gone through, and they were going to be there for each other. >> reporter: it turns out for more than six months the girls had been working on their plan to kill peyton lightner who they called bella. >> did you ever talk about killing bella in the bus at the birthday party? >> we did sometimes, but we made sure we whispered.

we used code words like, for knife, we used cracker. and for the killing we would use words like itch. >> reporter: the girls had multiple scenarios for the attack but were too scared to pull off the first two plans. finally, acting on their third idea. >> she was going to hide. and then morningmorgan and wher tackle her. like a lioness attacking a zebra. >> she passes the knife back to morgan and is like, all right, i'll do it if you tell me when to do it. >> so i started walking away. and when i was like five feet away, i said now. and i went, go ballistic, go crazy. make sure she's down. >> what did you do next? >> i already told you. >> what was that? >> stab, stab, stab, stab, stab,

stab. >> the girls were ultimately arrested for first degree attempted homicide. >> state of wisconsin versus morgan geyser. >> reporter: the two 12 year olds were to be charged as adults. >> seeing anissa in the courtroom in the jump suit with the shackles and the handcuffs and the belly chain, it broke my heart. >> that really started the whole split, i think, of public opinion on the case between those who saw it as these are dangerous actors out in the community that need to be locked up forever and those who thought they needed help and should be in juvenile court. >> reporter: detectives find a number of disturbing items in morgan's bedroom, including mutilated dolls and strange drawings. >> i was hired by the defense to evaluate morgan. i don't think she was deviously planning. i think she was feeling controlled by slender man. >> reporter: was it hard for to

you wrap your head around what had been done to you? >> after i heard why she had done it, i was like this doesn't surprise me at all. because she believed so hard in this thing that she would do anything for it. >> reporter: she had talked with her daughter about her interest in slender man but had no idea morgan thought it was real. as the legal process plays out, morgan undergoes a competency hearing during which it was revealed she was diagnosed with early onset schizophrenia. were you surprised? >> no. i wasn't surprised simply because there is a family history of schizophrenia. >> reporter: her father. >> yes, her father has schizophrenia. >> i expected to either get put in prison or an insane asylum. i didn't know what to expect. i don't think i'm insane, now. >> do you feel responsible? >> i think your job as a mother is to protect your children.

and to keep them safe. and of course, i felt as though i had failed. >> i was angry for a long time. especially morgan's parents. but i recognize that they're going through their own hell. >> reporter: both girls would plead not guilty by reason of mental disease or defect. anissa diagnosed with shared psychotic disorder. no question in your mind about where they should be? >> if they had stolen a candy bar, sure, that's a child. but they tried to kill somebody. >> reporter: they said anissa should be sent to a state mental institution. she strikes a deal avoiding prison as well. anissa is committed for 25 years, morgan for 40. >> i just want to let bella and her family know i'm

i never meant this to happen. >> i'm so sorry for what peyton went through. and for what they must have gone through. and i would take it back if i co d. >> reporter: peyton tells me has thought a lot about morgan's mother angie. >> i thought about what she's going through and how hard it must be for her. because i'm sure lot of people are saying it was her fought, th fault, that she raised her wrong, but it's not her fault, morgan's schizophrenic. i still sleep with a broken pair of scissors underneath my pillow just in case. >> reporter: do you think that will ever go away? >> i hope so, but for now i don't think so. >> reporter: we asked peyton about her one-time best friend, morgan. if she saw this interview, what would you want to say to her? >> ooh. there's a lot that i would want

to say to her. i would probably initially thank her, i would say, because of what she did i have the life i have now, which i really, really like it. >> reporter: you do know that when people hear you say i would probably thank her. >> mm-hm. >> reporter: that they're going to be surprised. >> yeah, i'm surprised to hear myself say that. >> reporter: why? >> because i wouldn't thi that someone who went through what i did would say that, but it's truly how i fileel, like withou the whole situation, i wouldn't be who i am. >> reporter: stronger. >> mm-hm. vicks vapopatch easy to wear with soothing vicks vapors for her, for you, for the whole family. new vicks vapopatch. breathe easy. of millions of americans during the recession. so, my wife kat and i took action.

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that's "nightline" for tonight. you can always catch our full episodes on hulu. thanks for the company, america. have a great weekend, goodnight.