IRS Criminal Investigation

The American system of taxation is based on voluntary compliance and on the premise that all income is taxable—including illegally earned income. IRS Criminal Investigation (CI) is the law-enforcement arm of the IRS. CI investigates potential criminal violations of the Internal Revenue Code and related financial crimes in a manner that fosters confidence in the tax system and compliance with the law.

In many instances, proving that a taxpayer willfully attempted to conceal income from the federal government is integral to proving other criminal activity, including fraud, money laundering, or violations of the Bank Secrecy Act. CI’s work helps ensure the integrity and fairness of our nation’s tax system.

Annual Business Report

The IRS CI Annual Business Report showcases significant investigations completed during the fiscal year and highlights major program areas.

Initiating an Investigation

IRS special agents must follow strict procedures to initiate an investigation and to recommend prosecution to the Department of Justice. These procedures include an initial analysis (“primary investigation”), supervisory review, and approvals by designated IRS officials to ensure investigations are based on factual evidence that tax fraud or another financial crime may have occurred.

Internal Revenue Manual

For detailed guidance, see the Internal Revenue Manual (IRM), Part 9 — Criminal Investigation, which outlines CI’s mission and strategies, investigative process, disclosure rules, and related procedures.