(Reuters) - One of two Wisconsin girls who said they stabbed a classmate to satisfy the fictitious horror character Slenderman agreed on Friday to plead guilty to avoid prison time, court documents showed.

Morgan Geyser’s official plea hearing is scheduled for Oct. 5 after an agreement was reached on the charge of attempted first-degree homicide, the documents showed.

Geyser, 15, will not be held criminally liable and instead remain at the state mental hospital where she has been getting treatment for about two years, according to Donna Kuchler, an attorney for Geyser.

The court plans to order further mental health evaluations.

“The results of those evaluations will help determine her placement,” Kuchler said in an email. “She has made incredible strides and is being properly medicated.”

The Waukesha County Circuit Courts jury on Sept. 15 found the other suspect, Anissa Weier, 15, was mentally ill during the May 2014 stabbing and was not responsible for her actions. Weier was sent to a state mental hospital, where she can seek a conditional release in July 2020, local media reported.

Geyser and Weier were charged with attempted first-degree homicide for the attack after a sleepover with their classmate in Waukesha, a Milwaukee suburb. All three girls were 12 at the time.

Weier and Geyser lured the victim into the woods and stabbed her 19 times with a kitchen knife to impress Slenderman, a tall, thin, creepy fictional bogeyman they insisted was real, according to a criminal complaint.

The character originated in 2009 as a meme, or a virally transmitted cultural symbol, in an online forum.

The victim survived the attack.