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 was finally coming to terms 
with exactly what I'd done.
بدأت أستوعب أخيراً ما أقدمتُ عليه
Da wurde mir endlich klar,
was ich getan hatte.
Por fin asimilé lo que había hecho.
Por fin asimilé lo que había hecho.
Eu estava finalmente me dando
conta do que havia feito.
Только тогда… я наконец поняла,
что натворила.