getting a bunch of number blogs names from someone with different email address's

I have anti splog plugin and didn't realize it was set to unlimited blogs per day I just changed it.
I have one person same IP use Different e-mail address's register blog names like
hlx01, hlx02, hlx03, hlx04, hlx05
why didn't anti splog catch this guy? I can't be leave that anti splog doesn't know about someone like this.
Is there a way I can check if this guy with all the e-mail address's and ip is listed?