MADISON, Wis. — A Wisconsin woman who admitted to nearly stabbing a classmate to death in 2014 to please the online horror character Slender Man is missing after she cut off an electronic monitoring device and left a group home, authorities said Sunday.

Madison police issued an alert Sunday for Morgan Geyser, now 23, saying she was last seen around 8 p.m. Saturday with an adult acquaintance.

“If you see Geyser, please call 911,” the alert said, adding that she had cut off a “Department of Corrections monitoring bracelet.”

Geyser was placed in a group home this year after being granted conditional release from the Winnebago Mental Health Institute. She was sent to the psychiatric institute in 2018 after pleading guilty to attempted first-degree intentional homicide in a deal with prosecutors to avoid prison.

Geyser’s attorney, Tony Cotton, did not immediately respond to a message left Sunday.

Authorities say Geyser and her friend, Anissa Weier, were 12 years old when they lured their classmate, Payton Leutner, to a suburban Milwaukee park after a sleepover. Geyser stabbed Leutner more than a dozen times while Weier egged her on. Leutner barely survived.

The girls later told investigators that they attacked Leutner to earn the right to be Slender Man’s servants and they feared he’d harm their families if they didn’t follow through.

Slender Man was created online by Eric Knudson in 2009 as a mysterious figure photo-edited into everyday images of children at play. He grew into a popular boogeyman, appearing in video games, online stories and a 2018 movie.

Weier pleaded guilty to attempted second-degree intentional homicide. She was also sent to the psychiatric center and granted release in 2021.