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've never given anyone 
something like this before...
...لم يسبق وأن أعطيتُ أحداً شيئاً كهذا
Bisher habe ich so was
noch nie getan,
Je n’ai jamais fait ça auparavant,
Non l'ho mai fatto in vita mia,
Nunca dei algo assim a ninguém antes...
Понимаешь, я ещё никому
такого не дарила…
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