I’m sorry to report that I had my first encounter with a tax client who has been a victim of identity theft in relation to their tax return.  I’m sure you are aware that Target, Home Depot, and Anthem were all compromised this past year so if you at any point did any business with one of these companies, you may be at risk.  You may not even realize there is an issue until you go to file your tax returns and the return is rejected because a SSN on the return has already been used to file (this is what happened to my client).

So what can you do to prevent this?  File Form 14039: Identity Theft Affidavit External Link with the IRS.  There is a fillable version of this form on irs.gov External Link and I believe that filing this will result in you being issued a special PIN number that must be used when filing your return to identify you as you and not someone else that may be using your SSN.
What happens if you’re a victim?  You need to do several things, only one of which will be filing a paper return if you are rejected.  Please read this Identity Theft Information for Taxpayers pamphlet from the IRS for detailed information.
Please note that you can pull all three of your credit reports once each year for free at annualcreditreport.com External Link.  This would be a great way for you to monitor your credit and make sure there are no possible attempts by others to access your credit.