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.
As long as you keep paying me, 
I'll let bygones be bygones.
طالما تدفع لي، سأدع الماضي في الماضي
Solange diese Zahlungen anhalten,
werde ich dich nicht verraten.
Finché mi pagherai,
Desde que você continue me pagando,
deixarei o passado para trás.
Будешь платить —
я тебя и пальчиком не трону.