Few of us want to pay taxes. But most of us are willing to do our civic duty and put some money in the pockets of Uncle Sam. Unfortunately, not everyone does this, putting a greater burden on everyone else. If you suspect an individual or business of committing tax fraud, you can help put an end to it by reporting it to the IRS.
Fill out IRS form 3949 A, detailing the type of tax fraud you suspect and providing information about the person you believe has committed the fraud. You have the option of identifying yourself, but it is not required.
Write a letter if you prefer not to use form 3949 A. The letter should include the name and address of the person you suspect, the individual's social security number or business' employer identification number, a description of the alleged fraud, the years it occurred, the estimated amount of unreported income and, if you want, your name and contact information.
Mail the form, or your letter, to: Internal Revenue Service, Fresno, CA 93888.