Morgan Geyser, who in 2014 stabbed a friend 19 times to appease the fictional character “Slender Man,” was located Sunday night after she allegedly cut off her Department of Corrections monitoring bracelet and left a Wisconsin group home where she had been a resident, authorities said.

Geyser was taken into custody in Posen, Illinois, police confirmed to ABC News.

Before being located, Geyser was last seen in Madison around 8 p.m. on Saturday with an adult acquaintance, police said in a statement posted on social media, which included a recent surveillance image of Geyser.

Geyser was found Sunday night at a Thornton’s truck stop with another person, according to Posen Police, who said the pair took a bus to Posen, and were both taken into custody.

Posen is about 25 minutes south of Chicago. 

The police department said it was notified of the 22-year-old Geyser’s disappearance on Sunday morning.

Geyser’s mother, Angie Geyser, said in a statement to ABC News earlier on Sunday, “If you see Morgan, please call the police. Morgan, if you can see this, we love you and just want to know you are safe.”

In March, Waukesha County Circuit Court Judge Michael Bohren ordered that Geyser be released from the Winnebago Mental Health Institute and sent to a group home after three psychologists testified she was prepared for supervised release.

As part of her release, Geyser was ordered to wear a monitoring bracelet.

Geyser, according to police, cut off her Department of Corrections monitoring bracelet and left the group home sometime Saturday night.

Geyser’s attorney, Tony Cotton, released a statement on Sunday asking Geyser to turn herself in, saying it was “in her best interest” to do so.

Geyser and another girl, Anissa Weier, were charged as adults and pleaded guilty to stabbing a classmate, Payton Leutner, 19 times in 2014, when they and the victim were 12 years old. Both Geyser’s and Weier’s guilty pleas were later vacated when they were found not guilty by reason of mental disease or defect. Both of them were subsequently sent to psychiatric institutions.

“Payton Leutner and her family are aware of the most recent situation regarding Morgan Geyser,” a spokesperson for the Leutner family said in a statement to ABC News. “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 continued. “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.” 

In January, Judge Bohren ordered the state Department of Health Services to come up with a plan for Geyser’s supervised release.

Geyser was transferred in March from the Winnebago Mental Health facility to a group home despite concerns raised by prosecutors, who alleged she had “violent” communication with a man outside the facility and had read a book in the facility with “themes of sexual sadism and murder.”

In 2014, Geyser and Weier lured their friend, Payton Leutner, then 12, to the woods in Waukesha, Wis., where Geyser stabbed Leutner while Weier watched.

Geyser and Weier left Leutner alone in the woods. Injured and bleeding, Leutner pulled herself to safety and was rushed to the hospital with life-threatening injuries.

Leutner survived the attack that captured headlines worldwide after Geyser and Weier claimed that the stabbing was intended to please “Slender Man,” a faceless, fictional internet-based character that garnered a cult-like following.

Geyser pleaded guilty to first-degree attempted intentional homicide and was sent to the Winnebago Mental Health Institute in 2018. Geyser was later found not guilty by reason of mental disease or defect, and was sentenced to up to 40 years in a psychiatric institution.

Weier was also found not guilty by mental disease or defect after pleading guilty to a lesser charge. She was sentenced to up to 25 years in a psychiatric institution. In 2021, at the age of 19, Weier was granted supervised release.

In an interview with ABC’s “20/20” in October 2019, Leutner said she had worked hard to heal from the attack and rebuild a normal life. She told ABC News that she was ready to reclaim her story.

“I’ve come to accept all of the scars that I have,” Leutner said in the exclusive interview with ABC’s David Muir. “It’s just a part of me. I don’t think much of them. They will probably go away and fade eventually.”

ABC News’ Victoria Arancio, Jason Volack and Jolloh Mariama contributed to this report.