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 couldn't bring myself to tell 
her to keep it a secret...
لم أستطع دفع نفسي على إخبارها 
...بالتكتّم على الأمر
Wie hätte ich ihr auch sagen sollen,
das geheim zu halten?
No podía pedirle
que lo mantuviera en secreto.
No podía pedirle
que lo mantuviera en secreto.
Con che coraggio avrei potuto chiederle
Não consegui dizer a ela para
guardar segredo, sabe...
Она так радовалась, что я не смогла…