The temp_ban column in the core_members table contains the banned state.
0 means not banned
-1 means banned
any other integer in this column is the timestamp until the user should be banned
It's going to move then and once they were moved, they'll be deleted.
BUT please be careful if you're using Forum Cover Images, they'll not be moved correctly due to a bug in the current release ( this will be fixed in the next release)