How to completely nuke and delete a spam account posting illegal content?

I am currently running a gitea as a service offered by a politically opinionated organization I am part of.
Say that a spammer creates an account and uses it to spam extremely illegal content in the various repositories of the instance, how do I completely nuke and delete from the entire system his account and anything he has ever posted or written?
We already have this issue in another service my organization offers, and we react to this by deleting the post and banning the IP, but gitea doesn’t seem to provide any obvious tool to deal with this kind of legally liable spam