The IRS has security measures in place to verify the accuracy of tax returns and the validity of social security numbers submitted. However, if you receive a notice from IRS that leads you to believe someone may have used your social security number fraudulently, please notify IRS immediately by responding to the name and number printed on the notice or letter.

You can contact the Federal Trade Commission (FTC) Identity Theft Hotline at (877) 438-4338 if you suspect someone else is using your social security number, or to secure information on how to prevent identity theft.

References:

• Identity Theft and Your Tax Records
• Reporting Suspected Tax Fraud Activity

Source: www.irs.gov