How Do I Contact the IRS Criminal Investigation Division?

To contact the IRS Criminal Investigation Division about suspected tax fraud, submit Form 3949-A through the online portal at IRS.gov/SubmitATip, or print the form and mail it to Internal Revenue Service, PO Box 3801, Ogden, UT 84409. If the tax, penalties, and interest in dispute exceed $2 million and you want a share of what the IRS collects, file Form 211 with the IRS Whistleblower Office instead. Criminal Investigation does not handle audits, billing disputes, or refund questions; for those, you need regular IRS customer service.

Pick the Right Form Before You File

Form 3949-A, Information Referral, is the general-purpose form for reporting a person or business you believe is violating tax law: unreported income, fake deductions, off-the-books wages, hidden accounts, and similar conduct.1Internal Revenue Service. About Form 3949-A, Information Referral Several situations use a different form, and using the wrong one slows everything down:

  • Tax preparer misconduct — a preparer who altered your return, inflated a refund, or filed without your consent — uses Form 14157, paired with Form 14157-A when you’re alleging fraud. Complaints more than three years old are generally not actionable.2Internal Revenue Service. Make a Complaint About a Tax Return Preparer
  • Promoters of abusive tax schemes (seminars, online pitches, packaged strategies) are reported on Form 14242. This targets the promoter, not people who bought in.3Internal Revenue Service. Form 14242, Report Suspected Abusive Tax Promotions or Preparers
  • Tax-related identity theft — someone used your Social Security number to file a return, or the IRS is asking about income you didn’t earn — uses Form 14039, the Identity Theft Affidavit. If you received IRS Letter 5071C, 4883C, or 5747C, follow that letter’s instructions instead.4Internal Revenue Service. When to File an Identity Theft Affidavit
  • Misconduct by a tax-exempt organization uses Form 13909, not Form 3949-A.5Internal Revenue Service. Form 3949-A, Information Referral
  • A whistleblower claim seeking a financial award uses Form 211. See the section below.

How to Submit Form 3949-A

You have two options. The online submission at IRS.gov/SubmitATip is the fastest and skips the mail entirely.6Internal Revenue Service. New IRS Online Tool for Reporting Suspected Tax-Related Illegal Activities Otherwise, download the PDF, fill it out, and mail it to Internal Revenue Service, PO Box 3801, Ogden, UT 84409.5Internal Revenue Service. Form 3949-A, Information Referral Use a tracked mail service and keep copies of anything you send. The IRS does not accept Form 3949-A by email.

What to Include

The more concrete your details, the more useful the referral:

  • The subject’s full name and address, and if you know it, their Social Security number or Employer Identification Number.
  • What they’re doing wrong: unreported income, fake deductions, cash wages, offshore accounts, whatever fits.
  • An estimate of the dollar amounts involved and the tax years affected.
  • Supporting documents you can point to or attach: bank statements, canceled checks, contracts, bookkeeping records. Evidence of intent is what separates a credible referral from a vague suspicion.

You don’t need all of this to file. Agents have access to tax records and financial databases that can fill gaps. But specific numbers and documents move a tip through intake far faster than a general complaint.

Filing Anonymously

You can leave Section C of Form 3949-A blank. The instructions state that your name and contact information are not required to process the report.5Internal Revenue Service. Form 3949-A, Information Referral The tradeoff: investigators can’t reach you for follow-up questions, so an anonymous tip needs to be as detailed and self-contained as you can make it.

The Whistleblower Track: Form 211

If you have specific, credible information about a substantial tax cheat, the IRS Whistleblower Program under Section 7623 of the Internal Revenue Code can pay you 15% to 30% of what it collects based on your information.7Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc

For a mandatory award in the 15–30% range, the tax, penalties, and interest in dispute must exceed $2 million. If the target is an individual, that person’s gross income must also have topped $200,000 in at least one of the relevant tax years.8Internal Revenue Service. Submit a Whistleblower Claim for Award Cases under those thresholds can still qualify for a discretionary award, but the amount is entirely up to the IRS.

Two other limits matter. If your claim relies mostly on publicly available information such as news reports or government hearings, the maximum drops to 10%. If you planned or initiated the illegal conduct, the IRS can reduce or deny your award, and a criminal conviction for that role means automatic denial.7Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc

Whistleblower claims use Form 211, Application for Award for Original Information, submitted online or by mail.8Internal Revenue Service. Submit a Whistleblower Claim for Award The form requires your identity and a signed declaration under penalty of perjury, so anonymous filing is not available on this track. Certain filers are ineligible entirely: current and former Treasury employees who got the information on the job, federal employees acting in their official duties, and anyone legally required or prohibited from disclosing the information.9eCFR. General Rules, Submitting Information on Underpayments of Tax or Violations of the Internal Revenue Laws, and Filing Claims for Award If you disagree with the final award determination, you have 30 days to appeal to the U.S. Tax Court.7Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc

What Happens After You File

Your referral enters an internal screening process. Special agents compare the details against tax records and financial databases to decide whether the case clears the threshold for a criminal investigation. That vetting can take weeks or months.

If the review confirms evidence of criminal activity, the case is assigned to a CI field office. Recommendations for prosecution move to the Department of Justice Tax Division for tax crimes, or to the relevant U.S. Attorney’s office for other financial crimes, where prosecutors decide independently whether to bring charges.10Internal Revenue Service. How Criminal Investigations Are Initiated A declined criminal case can still produce civil penalties.

Why You Probably Won’t Hear Back

After filing Form 3949-A, expect silence. Section 6103 of the Internal Revenue Code bars IRS employees from disclosing return information, so the agency cannot tell you whether your tip triggered an investigation, where it stands, or how it ended.11Office of the Law Revision Counsel. 26 USC 6103 – Confidentiality and Disclosure of Returns and Return Information An investigator may contact you for clarification or documents, but that’s the ceiling on communication. Silence does not mean your tip was ignored.

Whistleblower filers get a narrow exception. Under Section 6103(k)(13), the IRS must notify you within 60 days when your case is referred for audit, and again within 60 days when the taxpayer makes a related payment.11Office of the Law Revision Counsel. 26 USC 6103 – Confidentiality and Disclosure of Returns and Return Information You can also submit written requests for status updates, though the IRS can decline if disclosure would impair tax administration.