Hi and welcome to Just Answer!The form 3949A is used to report the suspected tax fraud to the IRS.If you suspect or know of an individual or company that is not complying with the tax laws, you may report this activity by completing Form 3949A. You may fill out Form 3949-A online, print it and mail it to:
Internal Revenue Service Fresno, CA 93888
If you do not wish to use Form 3949A, you may send a letter to the address above. Please include the following information, if available:
Name and address of the person you are reporting
The taxpayer identification number (social security number for an individual or employer identification number for a business)
A brief description of the alleged violation, including how you became aware of or obtained the informationThe years involved
The estimated dollar amount of any unreported income
Your name, address and daytime telephone number
Although you are not required to identify yourself, it is helpful to do so. Your identity can be kept confidential.
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