'Slender Man Stabbing' Defendant Morgan Geyser Sentenced to 40 Years in Mental Hospital

Morgan Geyser, 15, was committed to a mental health treatment facility for 40 years by a judge on Thursday, according to the Milwaukee Journal Sentinel.

Geyser took part in the "Slender Man Stabbing" back in 2014, where she and a classmate Anissa Weier led Payton Leutner into the woods in Waukesha, Wisconsin, where Geyser proceeded to stab her 19 times but did not kill her. The two girls both claimed afterwards that they were influenced by "The Slender Man," an Internet fictional character. All three girls were 12 years-old at the time of the attack.

Both girls were tried as adults for the attempted murder. Weier was sentenced to 25 years in a mental facility as she pleaded guilty to attempted second-degree intentioanl homicide as part of her plea deal.

Judge Michael Bohren opted for the maximum commitment term for Geyser so that she could recieve treatment for her diagnosed early-onset schizophrenia.

"We can't forget what actually happened," Bohren said according to the Journal Sentinel. "It was a premeditated murder."

A clip of Geyser's interrogation with the police following the attack was released to PEOPLE on Wednesday. The full clip will be shown on the upcoming series of 20/20 on ABC on Friday.

"Kill her," Geyser said when asked why she and Weier led Lautner to the woods. "I might as well just say it, we were trying to kill her.

"Do you know what happened to Bella," Geyser said. "She's not Anissa, she's the one whom I stabbed. ... Is she dead? I was just wondering."

ABC News interviewed Geyser's mother Angie for 20/20 episode.

"The interrogation is very difficult to watch because that's not my daughter saying those things. That's not the way that she speaks, that's not the way that she acts," Angie said.

Lautner has since made a full recovery from the attack, and her family released a written statement during the trial saying they want the defendant (Geyser) to get the proper treatment for her mental illness.

The case went on to be made into the HBO documentary Beware the Slenderman in 2017. The Slender Man character originated as a ficitional creation in 2009 but has since been made into the antagonist of multiple horror games and will be featured in the upcoming 2018 film Slender Man.

Photo: Twitter / @JournalSentinel, Rick Wood