One of the defendants in the now-notorious “Slender Man” stabbing case was sentenced Thursday to 40 years in a psychiatric institution. Morgan Geyser, 15, was ordered to receive treatment for schizophrenia by Circuit Judge Michael Bohren, according to the Milwaukee Journal Sentinel.

Geyser was accused of stabbing Peyton Leutner with a kitchen knife 19 times after luring her to the woods in 2014. Geyser and the other defendant in the case, Anissa Weier, left her for dead but Leutner was able to get help from a passerby. All three girls were 12-years-old at the time of the crime. Leutner survived, and Geyser and Weier were charged as adults.

Geyser previously pleaded guilty to attempted first-degree intentional homicide in the stabbing. Lawyers presented testimony from a doctor who said Geyser heard voices and her plea deal asserted she was not responsible by reason of mental illness.

“It was my opinion she was suffering under the effects of a psychotic spectrum disorder at the time the offense occurred,” psychologist Brooke Lumdbohm testified, according to WTMJ.

The 40-year sentence is the maximum allowed for the case. In a statement in court Thursday, Geyser expressed remorse for the crime.

“I’m sorry,” she said, according to WITI-TV. “I never meant this to happen.”

The other defendant in the case, Anissa Weier, was sentenced to 25 years in a psychiatric institution in December. The crime was dubbed the “Slender Man” case because Geyser reportedly believed she was able to communicate with the fictional, supernatural, blank-faced figure.

“I never would have imagined my daughter was capable of hurting another person,” Geyser’s mother, Angie, told ABC News. “They were just typical girls.”