Turns out the one spreading the rumors was Hashimoto, who did so at the behest of Sakayanagi. Shortly thereafter, Sakayanagi appears before Class C and she informs them she has evidence regarding the rumors about Ichinose.
the hurtful comments being 
perpetuated among you first-years.
بالتعليقات الجارحة المُتناقلة
بين طلّاب السنة الأولى
se estaban difundiendo
calumnias abusivas.
se estaban esparciendo
calumnias abusivas.
что вы, десятиклассники,
распространяете друг о друге гадости.