Yep; John Mark, a guard.
https://www.reddit.com/r/IAmA/comments/2y5sbt/iwasa_guard_in...
> I personally think Zimbardo is a self-promoting sensationalists more than a serious academic researcher and I think he was aware that this had the potential to make his career.
The aforementioned chat is a bunch of softballs. I do think this study warrants much more scrutiny.