Do you know that the delete function does not clear the space where
deleted file is located and just mark the entry in directory ( folder )
that the file is deleted?
That is why the file can be restored later, by you or by a bad guy that
thus would be able to get an access to your private files. You need to
use Wipe utility that will erase all information old (deleted) files
contain.
http://www.cezeo.com/