Jurors are having to decide whether Weier was mentally ill at the time of the attack at a park in the city of Waukesha, when all three girls were aged 12.
A second psychologist has testified about the delusional mental state of a girl who's admitted to helping stab a classmate almost to death in a Wisconsin park in 2014. Weier's attorneys are trying to convince jurors she was mentally ill during the attack and should be committed to an institution rather than prison.
Jurors will need to determine if the 15-year-old Weier was insane at the time she helped a friend stab a classmate in 2014, in allegiance to the fictional Slenderman character.
A jury determined Anissa Weier was mentally ill when she and Morgan Geyser lured Payton Leutner into woods in Milwaukee, United States, in 2014. She said most cases involve spouses, a parent and child, or siblings.
Circuit Judge Michael Bohren rejected an initial verdict presented at 8 p.m. because the jurors who agreed Weier had a mental condition weren't the same 10 who believed the condition prevented her from knowing her actions were wrong and conforming to the law. They claim she would have lost her only friend, Geyer, if she didn't follow through with plans to attack their classmate.
Prosecutors say a Wisconsin girl accused of helping stab a classmate to appease online horror character Slender Man participated in a cold and calculated attack.More news: Ghani To Off To New York For UN General Assembly
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"First of all, she was 12", Westendorf said, adding that Weier was influenced by a website focused on imaginary killers and boogeymen.
Defence attorney Joseph Smith Jr yesterday told Waukesha County Court: "Anissa's broken mind caused her to lose touch with reality".
Weier and Geyser told detectives they believed they had to kill Leutner to become Slender Man's servants and protect their families from him. The teen moved from apparent complete belief in Slender Man to a realization that she had been duped.
"I know now it's just teenagers who really like scaring people and making them believe false things", Weier told Waukesha Detective Michelle Trussoni.
Last month, Anissa Weier, 15, had pleaded guilty to attempted second-degree homicide due to mental illness or defect in the stabbing as part of a plea agreement. At 12 years old, she had no way to protect herself from (Slender Man) except for Morgan's advice and they swirled down into madness together'.
Geyser has pleaded not guilty by reason of mental disease to being a party to first-degree attempted intentional homicide.