Woman convicted in 'Slender Man' stabbing apprehended in Illinois after cutting off monitoring bracelet

The woman convicted of brutally stabbing her sixth-grade classmate to please the fictional horror character "Slender Man" was apprehended in Illinois after having left her Wisconsin group home, officials said.

Morgan Geyser, 23, cut off her Department of Corrections monitoring bracelet and left the group home Saturday night, the Madison Police Department said.

Police said they were notified at 10:34 p.m. Sunday that Geyser was taken into custody in Illinois. The Posen Police Department said officers were dispatched to Thornton's Truck Stop for a report of a man and woman "loitering behind the building."

When officers arrived, they found individuals sleeping on the sidewalk, Posen police said.

"The female repeatedly refused to provide her real name and initially gave a false one," Posen police said in a statement. "After continued attempts to identify her, she finally stated that she didn’t want to tell officers who she was because she had 'done something really bad,' and suggested that officers could 'just Google' her name."

Once she provided her true identity, however, police confirmed she was Geyser. Posen police said in a statement that the male with Geyser, who was not identified, was also taken into custody.

Geyser appeared in court on Monday and was ordered to be detained at Cook County Jail. The Cook County State’s Attorney’s Office said in a statement that an out-of-state warrant from Wisconsin was executed, and her next court date is Tuesday in Chicago.

Waukesha County District Attorney Lesli Boese told reporters that her office does not currently have jurisdiction in Geyser’s case as her group home was in a different county. The decision to charge Geyser in relation to the escape would fall to officials in Dane County, according to Boese.

The Dane County District Attorney’s Office did not immediately respond to a request for comment from NBC News on Monday.

A petition to revoke Geyser's conditional release in light of recent events would have to be filed by the state, which Boese said her office "fully" support. Geyser would be returned to full-time institutionalized care if her release was to be revoked.

"Not only should she have been in custody from 2014 forward, but also, attorney [Abbey] Nickolie argued vehemently for her not to be released to conditional release in I believe it was January of this year," Boese told reporters.

Wisconsin's Department of Health Services noted that Geyser is considered a patient, and therefore protected by patient privacy laws, limiting the agency's ability to comment on her case. The Department of Corrections is similarly limited, it added.

Morgan Geyser in a recent security video image. Madison Police Department

In an update earlier Sunday night, police included a tentative timeline covering Geyser's departure. The department said it was not notified of Geyser’s status until officers were dispatched to the group home Sunday morning based on a 911 call.

About 8:15 p.m. Saturday: Geyser was last seen at the group home.

Geyser was last seen at the group home. About 9:30 p.m.: The Department of Corrections was alerted that Geyser’s location tracker had malfunctioned.

The Department of Corrections was alerted that Geyser’s location tracker had malfunctioned. About 11:30 p.m.: The Department of Corrections reached out to the group home.

The Department of Corrections reached out to the group home. About 11:35 p.m.: Staff members at the home told corrections officials Geyser was not home and that she had removed her tracking device.

Staff members at the home told corrections officials Geyser was not home and that she had removed her tracking device. About midnight: The Department of Corrections distributed a request to other agencies that she should be apprehended if spotted.

The Department of Corrections distributed a request to other agencies that she should be apprehended if spotted. 7:46 a.m.: Someone from the home called 911 to report Geyser had vanished, characterizing her as a missing person.

Someone from the home called 911 to report Geyser had vanished, characterizing her as a missing person. 7:58 a.m.: Madison police were sent to investigate the missing person report.

The dispatch was "the first time the Madison Police Department was made aware that Geyser was missing,” the police department said.

The police department also said it did not receive the Department of Corrections' request for law enforcement to apprehend Geyser.

A judge ruled in January that Geyser should be released from a psychiatric hospital. She had spent nearly seven years in the Winnebago Mental Health Institute and was then moved to a group home.

Geyser was 15 when she was sentenced to a maximum of 40 years in a mental hospital for the 2014 stabbing attack. She and another girl lured their classmate Payton Leutner to a suburban Milwaukee park and attacked the girl, with Geyser stabbing her.

At the time, all three girls were 12 years old, and the victim barely survived.

Geyser and her classmate believed they had to attack the victim or risk having Slender Man, the fictional boogeyman, come after their families, defense lawyers said at the time.

Anthony Cotton, Geyser's attorney, shared a video statement Sunday on social media urging Geyser to turn herself in.

"We just heard the news that Morgan has walked away from the group home that she was housed at. Obviously it’s in her best interest to turn herself in immediately and not continue with this course of action," he said. "If anybody has contact with Morgan, hears from her, or if Morgan happens to see this, turn yourself in. Do not continue to remain on the run like this."

Leutner’s family said they were aware of Geyser’s disappearance.

“Payton and her family are safe and are working closely with local law enforcement to ensure their continued safety. The family would like to thank all of the law enforcement entities involved in the efforts to apprehend Morgan,” the statement said. “The Leutner family also wish to thank the outpouring of support from family, friends, and well-wishers who have contacted them during this difficult time.”

Police did not give more information about the group home Geyser left. The Department of Corrections has multiple programs for post-prison rehabilitation, drug treatment and supervision of those "conditionally released from mental health facilities," according to the website for the department's Division of Community Corrections.