Updated

A Delaware judge is set to rule on whether three teenage girls are culpable in a school fight that left a 16-year-old girl dead.

The judge plans to issue his ruling Thursday morning after presiding over a nonjury trial.

The girls, all 17, were tried as juveniles in the death of Amy Joyner-Francis after a fight captured on cellphone video at Howard High School of Technology in Wilmington. All three are charged with conspiracy, and one with criminally negligent homicide.

An autopsy found that Joyner-Francis, who had a rare, undiagnosed heart condition, died of sudden cardiac death, aggravated by physical and emotional stress from the April 2016 fight.

Defense attorneys argued that Joyner-Francis was a willing participant in a fight between "mutual combatants," and that her death was unforeseeable.