Leutner spoke about the life-changing encounter on 20/20 with David Muir. The interview will air ABC Friday at 9 p.m. ETD. In it, she speaks candidly about her relationship with the friends who tried to kill her, her recovery and her life after.

Leutner was 12 at the time of the attack, which was perpetrated by her 12-year-old friends Morgan Geyser and Annisa Weier. She was stabbed 19 times by Geyser while walking in the woods with the girls. It was Weier who told Leutner to lay on the ground. Leutner pulled herself from the brush to a public area, where she was found. After intensive surgery and recovery, Leutner recovered.

The survivor wasn’t surprised by the eerie motive. “After I heard why [Geyser] did it, I was like, ‘Well, this doesn’t surprise me at all because she believed so hard in this thing that she would do anything for it,” she said.

In the interview, Leutner also opened up about the former friends. She spoke on the controversy of the teens being tried in an adult court for the attempted murder. “Adult crime is adult court,” Leutner explained. “If they had stolen a candy bar, sure that’s a child. But you tried to kill somebody. That’s an adult crime.”

As for what she’d say to them now, Leutner has a note of thanks. “I would probably, initially thank her,” Leutner said of Geyser. “I would say, ‘Just because of what she did, I have the life I have now. I really, really like it and I have a plan. I didn’t have a plan when I was 12, and now I do because of everything that I went through. I wouldn’t think that someone who went through what I did would ever say that but that’s truly how I feel. Without the whole situation, I wouldn’t be who I am.”

In 2016, Geyser’s mother revealed that her daughter is schizophrenic. Both she and Weier were sentenced to 25 to 40 years in mental institutions in 2017.

The story inspired increased media attention to the Slenderman character, as well as to the control the figure has on impressionable children. The character, which first surfaced online as a creepypasta horror image. A documentary on the topic, Beware The Slenderman, was released on HBO in 2016. There are also several horror films about the figure.