That's actually one of the things I've done. But this particular person either got wise in general or looked back through the community at the post where we informed our other players of what they were doing and figured out how we found out. So now, they're using different emails for each of their aliases.
As of right now, all my co-mod and I have to go on are common mannerisms we've picked up on and character archetypes that they always seem to apply with, but that's difficult, and probably not enough basis to remove them without a ton of backlash. You know?
Thank you for your help. I'm seriously at my wits end here.