Internal FTP user list?

Apologies in advance if this has been covered in another thread -- I couldn't find it.

Does cPanel keep an internal FTP userlist? If I clear out the proftpd passwd file, it's regenerated when changes are made, so the answer seems to be 'yes'. I haven't been able to locate this, and unfortunately we have a big list of bad FTP accounts.

(For the record, we're running Pure, but it's using the proftpd password file, so I assume the problem isn't actually related to Pure at all.)

If my assumption is incorrect, any thoughts on deleting the unwanted accounts?

TIA

- technicals