If you're tempted to use this application that goes by the name of "Loyalfriend" - don't! Not only you won't be able to see who has deleted you from their list of "friends", but you'll also be giving the application permission to access your basic information, send you e-mails, post on your wall and change information on your page.
Once the application is allowed to do these things, the same message for which you fell for will appear on your wall. Also, once it is installed, you will be redirected to a typical complete-this-test/survey-to-prove-you-are-human page where you will also be asked to give up your mobile phone number. If you do, you're probably going to be surprised with additional expensive charges on your monthly bill.
If you have fallen for this scam, Facecrooks advises cleaning up your newsfeed and removing the application from your profile, and contacting your mobile carrier to avoid being charged.