Two Wisconsin girls accused of trying to kill a classmate to please the fictional character Slender Man will go before a judge considering their competency to stand trial.

Defense attorneys are challenging findings from state doctors that the girls are fit to stand trial on attempted homicide charges. Waukesha County Circuit Judge Michael Bohren is scheduled to hold back-to-back hearings for both girls on Thursday.

Court documents say the girls plotted for months to kill their friend before they attacked her in May in a Waukesha park. The victim was stabbed 19 times but survived.

All three girls were 12 at the time. The Associated Press is not naming the alleged attackers because their attorneys have said they will seek to have the cases moved to juvenile court.