DBF file exist while user has been dropped?
Datafiles are allocated to tablespaces, not users. Dropping the users will remove the tables etc. from the tablespace, but the underlying storage is not affected.

Don't delete the dbf files from the filesystem directly, you'll get your database into a mess. To remove them, find which tablespace the files belong to using the following statement:

select tablespace_name
from   dba_data_files
where  file_name = &lt;file name with full path&gt;;


You can then remove the file(s) by dropping the tablespace:

drop tablespace &lt;tablespace_name&gt; including contents and datafiles;


Before doing this you should verify that there aren't any objects still allocated to the tablespace for other users however. You can find this by running:

select * from dba_segments
where  tablespace_name = &lt;tablespace to drop&gt;;


If this returns anything, move the objects to another tablespace if you want to keep them before dropping the tablespace.