ABC News December 21, 2017

Teen who pleaded guilty in Slender Man stabbing case to remain in institutional care for 25 years, judge says

WATCH: Teen who pleaded guilty in Slender Man stabbing case to remain in institutional care for 25 years, judge says

A judge has sentenced one of the two Wisconsin teenagers accused of stabbing their friend in the woods to please the online fictional character Slender Man.

Anissa Weier, 16, will now spend 25 years under a mental health institution’s supervision, with credit for her 1,301 days already spent in incarceration. More than two years and six months of her sentence will be spent in a mental hospital before she can petition the court for release every six months. If released, Weier will remain under institutional supervision until year 2039 and will be 37 years old.

“I just want everyone involved in this to know that I do hold myself accountable for this,” Weier told the court. “I want everybody involved to know that I deeply regret everything that happened that day, and that I know that nothing I say is going to make this right, your honor, and nothing I say is going to fix what I broke. I am just hoping that by holding myself somewhat accountable and making myself responsible for what I took part in that day, that I can be responsible and make sure this doesn’t happen again. I’m never going to let this happen again.”

Weier pleaded guilty earlier this year to attempted second-degree intentional homicide, as a party to a crime, with the use of a dangerous weapon as part of a plea deal. A jury then found Weier not guilty by reason of mental disease or defect.

Earlier this year the court also accepted a plea deal for co-defendant Morgan Geyser, who pleaded guilty to attempted first-degree intentional homicide. In accordance with the plea deal, the court also found Geyser not guilty by reason of mental disease or defect despite her earlier guilty plea. Geyser’s sentencing is set for 2018.

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In a victim impact statement, Stacie Leutner, mother of the stabbing survivor Payton Leutner, wrote that she and her family accept the plea deals but petitioned Judge Michael Bohren to “consider everything Payton and those closest to her have endured over the last three-and-a-half years” prior to the sentencing.

In the victim impact statement, Stacie Leutner wrote that some of her daughter’s wounds from the attack still “tingle and ache and remind her of their presence every day.”

“Shopping for homecoming dresses leaves only a few options because far too many dresses will show off her scars,” Stacie Leutner wrote. “Beach vacations are harsh reminders that swimsuits aren’t made for young girls with 25 scars.”

The lingering physical pain from being stabbed 19 times in the attack, Stacie Leutner wrote, is only part of the trauma that “has defined our lives” for three-and-a-half years.

In spite of what Stacie Leutner describes as the appearance of a quick recovery since the attack, she wrote “[Payton] held everyone at arm’s length and never let anyone get too close. She immersed herself in school in an attempt to distract herself from the uncertainty of her life.”

“We accepted the plea deals for Morgan and Anissa for two reasons,” Stacie Leutner wrote. “First, because we believed it was the best thing to do to ensure Payton would not have to testify. Traumatizing her further didn’t seem worth it. She has never talked about her attack so asking her to testify and relive her experience in front of a courtroom of strangers felt cruel and unnecessary. And second, because Payton felt placement in a mental health facility was the best disposition for both girls.”

Although she has accepted the plea deals, Stacie Leutner writes that her daughter “still fears for her safety.”

Weier and Geyser were arrested May 31, 2014, after the stabbing of Payton Leutner, whom they left in the woods in Waukesha, Wisconsin. Leutner crawled to a nearby road and was helped by a passing bicyclist before she was hospitalized with life-threatening injuries but survived. Weier, Geyser and Payton Leutner were 12 years old at the time.

Prosecutors have said that both girls were obsessed with the character Slender Man, who is often depicted in fan fiction stories online as a horror figure who stalks children.

In January, Weier's parents told “Good Morning America” that their daughter had expressed remorse.

Her mother, Kristi Weier, said that according to police interview tapes of Geyser and her daughter, "They thoroughly believed that Slender Man was real and wanted to prove that he was real."

Her father, Bill Weier, said that if he had the chance to meet Payton Leutner's family face to face, "I would tell them I'm sorry. I would tell them that I'm thankful that Payton survived. And I would tell them that for as much as they are struggling with trying to process this in what happened to their daughter, we are struggling equally trying to process this with what happened not only to their daughter but to our daughter."