A set of 13-year-old girls accused of attempting to kill their friend as a sacrifice to a horror fiction character called Slender Man sat quietly in court Friday, prompting the judge to issue a not guilty plea.

Attorneys for every girl said after the hearing they believe the case must be tried in juvenile court.

Investigators say the suburban Milwaukee girls plotted for months to bound Payton Leutner after a sleepover.

Slender Man stories have proliferated lately, and the ladies wanted to kill for him, in part, to demonstrate his existence, authorities say.

The women, 12 at the time of the stabbing, considered they would possess a home in Slim Guy’s mansion after killing Payton, authorities say.

After stabbing the girl and leaving her for dead, the girls started walking to a forest 300 miles away, w they believed Slim Man lived, authorities say.

The Associated Press has not identified the girls because an appeals court could transfer their cases to juvenile court, w proceedings are closed to the public.

Tony Cotton, who has been the lead attorney for one of the girls, said ahead of the hearing that his client would enter pleas of not guilty and not guilty by reason of mental disease or defect.

The girls face 65 years in prison if convicted as adults.