Transcript for Slenderman Trial: Young Suspects Deemed Competent
major development in case that shocked parents around the world. The two 12-year-old Wisconsin girls accused of luring their friend into the woods and then stabbing her 19 times and leaving her for dead. All to impress a character they learned about on the internet. Now a big court ruling. Here's ABC's Alex Perez. Reporter: Girls just 12 and 13 years old. Yet accused of a brutal crime. Stabbing a friend 19 times and leaving her for dead. All to please a fictional horror character, made up on the internet, today, a judge finding both Anissa and Morgan competent to stand trial. The judge wouldn't let cameras in court. We could hear Anissa. I consider myself incompetent, sir. Reporter: The judge disagreed. She's competent to be able to make the decisions that need to be mad. Reporter: This testimony after two doctors. The court has officially said I believe they're competent to stand trial, they understand the proceedings against them. They can assist in their defenses. Reporter: The judge later found Morgan geyser competent after her lawyers waived her right to a hearing. The two girls are likely to be tried as a adults. In Wisconsin, anyone older than 10 is presumed to be an adult. The parents of Payton sat down with David Muir for this. It's about making sure Payton feels safe and that she can move on with the rest of her life with no fear. Reporter: It all started seven months ago in Wisconsin, just outside of Milwaukee. Appears to be stand. She appears to be what? Stabbed. Reporter: The three girls were on a birthday sleepover where they went missing. Payton came crawling out of the woods with wounds. They had run away and the police hadn't found them yet and we just knew that Payton told us that Morgan stabbed her and the police hadn't been able to find the girls. Police believed those girls were walking. Yeah. They were going to find a mansion in the woods. Yeah, the mansion in the woods. Reporter: Slender man a fictitious character that the girls wanted to impress. A major search by ground. Police are still on the scene here. Two 12-year-old girls stabbing their friendly nearly to death is unimaginable any time, but especially for a safe community like this city. Reporter: Five hours later, police found the girls along interstate 94, a knife with a 5-inch blade in one of the girls' bags. The knife from the stabbing was located in the backpack that was in the possession of the two suspects. Reporter: Police say they were carrying clothes, gra Nola bars, water bottles. One girl was carrying her parents. Neither girl put up a fight and were taken into custody and questioned. Payton's parents were asking her what happened, too. Has Payton talked at all about the horror of that moment sf. She told me she was scared. She said all I remember is the pain. How well did you know these two other girls. Payton's best friend. Any red flags. They would have arguments. Reporter: What drove best friends to allegedly to commit such a heinous crime? They told police it was their devotion to slender man, who lurks in the background of images, sometimes appearing over the shoulders of children. Giving this fictional character new life every day. It's the thing that we fear that we don't actually see. What was shocking to me how planned out this was. Anissa revealed that it was Morgan's idea to kill Payton. Payton's parents took David to those woods and recalled their daughter's harrowing story. She told me she didn't want to play hide and seek in the woods. She said she was forced to go. Reporter: The girls told police about that game of hide and seek. Anissa and the victim were hiding. Reporter: Anissa tells police that she sits on Payton and she couldn't breathe. At that point, one girl says to the other, just go crazy. Yeah, yeah. Reporter: A short time later, Anissa tells police that Morgan takes the knife, I'm not going to until you tell me. Payton is stabbed 19 times, stumbling trying to get up. Where on Earth do you think she got the strength to crawl out of those woods. We asked her and she said, I wanted to live. Reporter: Today Payton has recovered from her wounds. Her bedroom is covered in purple hearts, messages of support that she has received from around the world after that horrible day. Now, Morgan and Anissa await their trial. Pretrial hearings, motions, they all begin now. Now that the court has said, they're competent to stand trial. Reporter: For "Nightline," I'm Alex Perez. Next, she acts, produces and
This transcript has been automatically generated and may not be 100% accurate.