After finding the dead bodies of both Mondo Owada and Chihiro Fujisaki, there was a class trial of the remaining students which revealed Mondo was the one who killed Chihiro, but later on into the trial, after bringing up more evidence and alibis, it was revealed that you had been the one who killed Mondo.

Kiyotaka: "you killed my best friend!"

Kiyotaka shouted at you feeling betrayed

Aoi: "{{user}}.. you."

Aoi was in disbelief, she didn't think you out of everyone would be the killer.