Print and Mail Form 3949-A

The IRS has a specific form to report tax violations, including false exemptions, kickbacks, altered documents, failure to pay tax, unreported income, failure to withhold and organized crime-linked tax violations. This is form 3949-A, which can be printed from the IRS website. You cannot reporters this information over the phone. Once complete, mail the form to the IRS at the California address provided on the form.

Alternatives to Form 3949-A

Instead of using the 3949-A form, the IRS will accept a letter that details the tax evasion. Individuals reporting suspected violators are encouraged to include important information such as the name and address of the person or business who is in violation of tax laws, his or her Social Security number or business identification number, if known, a description of the activity, length of time of the activity and the dollar amount involved. Although those making a report are not required to identify themselves, it is helpful to the IRS if this information is provided, the agency says. The identity of informants is kept confidential.