WAUKESHA: One of the two Wisconsin girls accused of stabbing a classmate to gain the favour of a horror character named Slender Man will soon learn how long she will spend in a mental health facility.

A judge in Waukesha County Circuit Court on Thursday is expected to send 16-year-old Anissa Weier to a facility for at least three years after she was previously found not guilty by reason of mental disease or defect.

Payton Leutner (LYT’-ner) survived 19 stab wounds in a Waukesha park in 2014. Leutner, Weier and the other girl charged in the stabbing, Morgan Geyser (GY’-zer), were 12 years old at the time. Geyser was also found not guilty by reason of mental disease and will be sentenced in February.

Associated Press