[DezoPenguin]

Originally Posted by Lord of Fire

Spoiler:

I've read rumors that it was Izumi's older brother, Kazuma. However, the only thing I could find on him is that he was mentally unstable and committed suicide around the time Reiko/Ms Mikami got murdered, so I don't know how credible that rumor is.

Spoiler:

That would be an excellent rumor if true, because it would make the poignancy of Kouichi's forgetting his first meeting with Izumi all the worse, because it would mean that they'd been drawn together by the initial tragedy.