What process do you have to stop this spammer sighing up again. It sounds like you already have some automation, but in this case it got flagged for manual review.
It seems this is part of the automation, it got flagged based on this.
By the way, I am quite happy with JavaScript based spamfilters, they work quite well for small websites. The service Stop Forum Spam is something that seems fit for this, also at bigger scale. I assume Akismet might be good too, but it is somewhat leaky in privacy, depending on what you send to it.
Are there any other filters you recommend?