A Wisconsin woman involved in a notorious Slender Man stabbing case is missing after leaving a group home, officials said Sunday. Morgan Geyser, 23, cut off her electronic monitoring device and was last seen around 8 p.m. Saturday with an adult acquaintance, Madison police said. Authorities urged anyone who sees her to call 911 immediately. Geyser’s disappearance comes after she was placed in a group home this year. She had been conditionally released from the Winnebago Mental Health Institute, where she was sent in 2018 following a guilty plea to attempted first-degree intentional homicide. Her plea deal spared her from prison. Her attorney, Tony Cotton, said he does not know what happened and urged Geyser to turn herself in. “It’s in her best interest for her to turn herself in immediately and not continue with this course of action,” Cotton said in an Instagram video. “We don’t know any of the facts about what happened or who might have assisted her.” Geyser and her friend, Anissa Weier, were both 12 years old when they attacked their classmate, Payton Leutner, in 2014. The girls lured Leutner to a park near Milwaukee after a sleepover. Geyser stabbed Leutner more than a dozen times while Weier encouraged her. Leutner survived the brutal attack. The girls later told investigators they carried out the stabbing to serve the online horror character Slender Man. They feared the fictional figure would harm their families if they did not obey. Slender Man is a digital creation by Eric Knudsen from 2009. The tall, faceless figure first appeared in manipulated photos and quickly became a popular internet legend. The character has since appeared in video games, online stories, and a 2018 film. Weier pleaded guilty to attempted second-degree intentional homicide. She also spent time in a psychiatric center and was released in 2021. Authorities are now searching for Geyser, emphasizing public safety and urging anyone with information to call 911. Police stress that Geyser is considered a missing person rather than an immediate threat, but her history and the removal of her monitoring device make her case urgent. Geyser’s story has drawn national attention due to the unusual circumstances of the original stabbing and her ties to the Slender Man phenomenon. Experts note that her conditional release included strict supervision, making her sudden disappearance a serious concern for authorities. The 2014 stabbing shocked the nation and highlighted the dangers of online myths influencing children. Psychologists have since studied the case to understand how fantasy figures can affect impressionable minds. As police continue to search, community members are reminded to report any sightings and avoid confronting Geyser directly. Officials say the focus is on ensuring she receives help while keeping the public safe.