That's my guess too since Iijima and Shikimi scammed vulnerable men into lending them money, which might have sent them into debt or something similar.I'm guessing it's a victim of the badger schemes. They killed Ijima who as far as we're aware, was only affiliated with the bullies through Shikimi. Nothing suggested he was joining them in tormenting kids at school. Hell, I thought he was past high school.
So I guess she still loves her husband, but she feels tainted now and she needs to complete her revenge.
So the bad guys know they are being killed off?