IRS Criminal Investigation, Explained

Most people think of the IRS as a giant billing department. Notices, transcripts, payment plans. That is the civil side, and it is most of what the agency does.

There is another side. IRS Criminal Investigation, usually called IRS-CI or just CI, is the law enforcement arm of the IRS. Its people are special agents. They carry badges and credentials, and they investigate crimes. They do not collect taxes. They build cases that prosecutors may take to a grand jury and a federal courtroom.

If you have any reason to think CI is interested in you, this is the first page to read. Then the next phone call should be to a lawyer, not to the agent.

The mission, in the IRS's own words

The Internal Revenue Manual sets out CI's mission in IRM 9.1.1.2. CI "serves the American public by investigating potential criminal violations of the Internal Revenue Code (IRC) and related financial crimes in a manner that fosters confidence in the tax system and compliance with the law."

Two pieces of that sentence matter. First, "potential criminal violations of the Internal Revenue Code." That covers the core tax crimes: tax evasion under section 7201, willful failure to collect or pay over tax under section 7202, willful failure to file under section 7203, and false returns under section 7206. Second, "related financial crimes." CI investigates more than tax, and the manual lists money laundering, international, and terrorism strategies alongside its compliance strategy in IRM 9.1.1.3.

The phrase "fosters confidence in the tax system" tells you something about how cases are chosen. Criminal tax prosecutions are partly about deterrence. The Justice Manual says so directly in JM 6-4.010: criminal prosecutions punish violators and deter others.

Civil agents and special agents are not the same people

This is where people get hurt. A revenue agent conducts audits. A revenue officer collects unpaid tax. Both are civil employees. A special agent is a criminal investigator.

The difference shows up in how they talk to you. In a civil audit, the examiner wants documents and explanations so the tax can be computed. In a criminal investigation, the special agent wants evidence, and statements you make are evidence. IRM 9.4.5 directs special agents to give the subject of an investigation a rights statement in a non-custodial interview, telling you that you cannot be compelled to answer questions that might tend to incriminate you, that what you say may be used against you in a criminal proceeding, and that you may seek the assistance of an attorney before responding.

If someone reads you that statement, you are not in an audit anymore. Read your rights in an IRS criminal interview.

Where CI cases come from

CI does not pick names out of a hat. The Justice Manual, at JM 6-4.110, says CI generally opens investigations as a result of:

• Fraud referrals from other divisions within the IRS
• Information provided by other government entities
• Information provided by private parties
• Matters or projects developed within CI

The CI manual describes the same pipeline from the inside. IRM 9.4.1.4.1 lists sources of primary investigations, including information items and whistleblowers, refund fraud and investigative support, criminal fraud referrals, and grand jury evaluation requests.

The fraud referral is the source most ordinary taxpayers should understand, because it starts in a civil audit. When a revenue agent or revenue officer finds what the manual calls firm indications of fraud, a formal referral to CI can follow on Form 2797. That process is covered in when an audit turns criminal.

The whistleblower source is the one people forget. An ex-spouse, a former bookkeeper, or a business partner can file information with the IRS. Under IRM 9.4.1.4.1.1, information tied to a signed Form 211, the whistleblower award application, gets reviewed by the CI field office to decide whether a primary investigation is warranted.

How a CI investigation is structured

CI's own manual describes stages. A general investigation looks at a broad area or scheme. A primary investigation evaluates a specific lead. A subject criminal investigation is a numbered case against an identified person or entity. IRM 9.4.1 covers all three.

The step from a primary investigation to a subject criminal investigation is significant. In the fraud referral process, IRM 25.1.3.5 says that if CI accepts a referral, the primary investigation is elevated to a subject criminal investigation.

Investigations come in two flavors, and the difference matters for your rights and for what the government can do:

• Administrative investigations. CI uses its own tools, including IRS summonses, interviews, and records requests. When the investigation is complete, the special agent writes a special agent's report recommending prosecution.
• Grand jury investigations. A federal prosecutor runs the investigation through a grand jury, with grand jury subpoenas. Under JM 6-4.120, the Justice Department must authorize the use of a grand jury for criminal tax violations. Read more in grand jury subpoenas in tax investigations.

What happens when CI finishes

CI does not prosecute anyone. Prosecutors do. JM 6-4.110 describes the handoff. After an administrative investigation, the special agent prepares a special agent's report with exhibits. It is reviewed by CI supervisors and by IRS Chief Counsel's Criminal Tax attorneys, who prepare a criminal enforcement memorandum. If CI concludes the case should be prosecuted, the Special Agent in Charge refers it to the Justice Department or, in some cases, directly to a United States Attorney's Office.

At that point, the Code changes the rules for the IRS. Under IRC 7602(d), once a Justice Department referral is in effect for a person, the IRS may not issue an administrative summons or begin an action to enforce one with respect to that person. The case is now in the hands of prosecutors and, often, a grand jury.

The Justice Department's own review process is covered in how the Justice Department reviews criminal tax cases. One note on structure: the Justice Manual still assigns criminal tax review to the Tax Division, but the Department's fiscal year 2026 budget exhibits proposed realigning the Tax Division's criminal work into the Criminal Division, and justice.gov now files the Tax Division's home page under its archives. The names on the letterhead may change. The process described in the manual is what is published today.

What CI is not allowed to do

CI special agents are law enforcement officers, and they are bound by the Constitution like any other federal agent. They need a warrant to search your home or office. The IRS manual adds its own restraint: IRM 9.4.9.2 says search warrants for tax and tax-related offenses "will be utilized with restraint and only in significant tax investigations," and directs agents to consider less intrusive means first. See IRS-CI search warrants.

They also cannot make you talk. That is the most practical protection you have, and it only works if you use it.

Why this matters to an ordinary taxpayer

Most tax problems are civil, and most people who owe the IRS money will never meet a special agent. Owing tax is not a crime. Not being able to pay is not a crime.

What turns a tax problem into a criminal one is willfulness, which the IRS manual defines in IRM 25.1.1.5 as a voluntary, intentional violation of a known legal duty. If your situation involves income you deliberately left off returns, records you know are false, or assets you moved to keep them away from the IRS, you are in a different category. Read willfulness in criminal tax cases before you decide anything.

If you are in that category and nobody from the IRS has contacted you yet, you may still have an option. The IRS Criminal Investigation Voluntary Disclosure Practice exists for taxpayers with criminal exposure who come forward before the government finds them. Timing is the whole game. Read the Voluntary Disclosure Practice guide.

The short version

CI is a criminal investigative agency inside the IRS. It gets cases from fraud referrals, other agencies, private parties, and its own projects. It investigates administratively or through a grand jury, and it hands finished cases to federal prosecutors.

If CI is involved, the conversation you have next is not a customer service call. It is evidence. Get a lawyer between you and the agents before anyone asks you a question.

General information only, not legal advice. Reading this page does not create an attorney-client relationship. Laws and IRS procedures change; the sources cited were reviewed on the date shown above.