Letter 4674C explains procedure, problems or advice regarding a potential Identity Theft Claim. You will (or have) likely receive Letter 5073C and Notice CP01. Once the claim is processed, the IRS will assign you a special ID code to place on your subsequent 3 years of returns so they can track any possible fraud.
However, this procedure takes a very long time and it is very difficult to contact anyone regarding your case. But, eventually you will receive a notice about the status. Start the process by filing Form 14039.
Response to Letter 4674C
While the claim is awaiting IRS attention, take the IRS advice: notify local law enforcement and keep watch of your financial accounts. You might also call the IRS at 1-800-829-1040 and order your Account Transcripts and your Wage & Income Transcripts. These documents tell you what has been filed for you by 3rd parties and any activity on your IRS account. You can verify the accuracy of your income & filings and detect any ID theft or fraud against you.
For more in-depth advice, forms, and instructions follow the Prep Steps so we can create an Action Plan to avoid this problem forever. Also, read our Blog title "ID Theft - Fraud" for more information!