Check out the event lot page in the ACP (under advanced). The user's deletion event should have been logged, and the IP address should have been saved.
... as long as your NodeBB is new enough, that is 🙂
@julian Heh, nor I. Just wasn't feelin' it. Enjoy good craft brews but not into getting plastered for the sake of getting plastered. Wife and her sis put away some Guinness though. But then they're also half Irish so it was pretty much obligatory.