A pair of 13-year-old Wisconsin girls accused of luring their friend into the woods to stab her as a sacrifice to the fictitious horror character Slender Man are set to formally enter their pleas in the case.

The suburban Milwaukee teens are being tried as adults and face decades in prison in connection with the 2014 attack. They are expected to appear in court for an arraignment hearing Friday.

Investigators have said the two plotted to lure Payton Leutner into the woods after a sleepover. They say the girls intended to kill Payton to win the favor of the horror character. Leutner was stabbed 19 times but survived.

The Associated Press hasn't identified the girls because an appeals court could move their cases to juvenile court, where proceedings are closed.