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.
Be very quiet, everyone.
الزموا الهدوء جميعاً
Seid ruhig.
Fate silenzio, prego.
Fiquem quietos, pessoal.
Я попрошу сейчас тишины!