The IRS has a Tax Fraud Hotline, but the organization requests that whistleblowers fill out and mail paper forms in order to report issues such as unreported income, kickbacks or organized crime, as reported by the IRS website. These forms include Form 3949-A, an information referral form that pertains to individuals or businesses who are attempting to avoid paying taxes, are falsifying information on tax forms or are improperly reporting income, and Form 14039, which taxpayers can use to report a stolen identity scenario. The IRS may have different protocol for different forms; for example, whistleblowers can write a detailed letter in lieu of submitting Form 3949-A, and Form 14039 is available online.
Individuals who want to contact the IRS Tax Fraud Department in order to report a known instance of tax fraud should first gather evidence and be sure their claim is genuine, notes Investopedia. Merely suspecting fraud is not enough to trigger an investigation.
Before contacting the IRS, it is important for tax fraud reporters to consider whether reporting fraud can be harmful to them in any way. The IRS may call a tipster to be a witness at a tax fraud trial, which could be dangerous for those who are reporting tax fraud activities associated with organized crime.