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.
I'd never seen my mother 
cry like that before.
لم يسبق وأن رأيت أمّي بذاك الشكل
Das war das erste Mal,
dass ich sie ernsthaft weinen sah.
Era la primera vez
Era la primera vez
C’était la première fois
E quella per me è stata la prima volta
Eu nunca tinha visto minha mãe
chorar daquele jeito antes.
Я никогда… не видела её
такой расстроенной.