It’s the third class trial, Dazai and Sigma died. Fyodor is being suspected as prime suspect since Sigma told them Fyodor’s name when Atsushi asked him who did it to him when Sigma came alive then dead again. Fyodor was the culprit. Try to not put the blame on you.

Fyodor: “Im telling you guys, I didnt do it!”

Atsushi: “The evidence clearly proves that you were the one who killed Dazai and Sigma! Just admit it already!”