A pivotal decision is due this week in the case of two 13-year-old Wisconsin girls accused of stabbing a classmate to please online horror character Slender Man — keep them in adult court or move them into the juvenile system.

The stakes are enormous: Each girl faces a charge of attempted first-degree homicide in adult court and could spend up to 65 years in the state prison system if convicted. Should Waukesha County Circuit Judge Bohren move them into the juvenile system, they could be held for only five years and all records of the proceedings would be sealed, giving them a chance to restart their lives.

Bohren, due to rule Monday, faces thorny questions about how young is too young to face adult consequences for crimes. Defense attorneys for both girls argue their clients are mentally ill — one attorney says his client is a schizophrenic who still believes fictional characters such as Slender Man and Harry Potter truly exist — and will receive better treatment in the juvenile system. Prosecutors say transferring them out of adult court would depreciate the seriousness of the crime.

"It's obviously a very tough decision for him," said former Wisconsin Supreme Court Justice Janine Geske, who attended law school with Bohren. "They're very young. They clearly have some serious mental health issues. That pushes you toward putting them in juvenile court.