This very point was covered by "Computeractive" Magazine (it's a UK computer magazine) in issue 366 of 1. March - 14. March 2012 (p33). This is what the magazine said:
If you wish to close your Facebook account, begin by clicking the small down-pointing arrow at the top right of your profile page and choose Account Settings. Now click Security on the left-hand side to see a 'Deactivate your account' link: clicking this and following the prompts will disable your profile but won't delete your information. The option to delete an account properly is hidden: click on Help at the bottom of the page and type delete my account into the search bar. Click on the first article, entitled 'How do I permanently delete my account?' This provides a link to the deletion-request form. It takes two weeks for a Facebook account to be deleted, and if you log into it in the meantime the request will be cancelled, so make sure you stay away.
Also try this blog:
http://romcartridge.b...facebook-account.html