Analysis

What to do When Under Investigation For Proffer Agreement Defense

July 2026 · 6 min read · John D. Kirby, Former Federal Prosecutor

When you learn that a federal investigation might be targeting you specifically or your organization generally, it is crucial to act quickly and wisely. Investigations often start innocuously—routine inquiries by agents or grand jury subpoenas for documents—and escalate rapidly.

Federal investigations typically involve multiple agencies including the FBI, DEA, IRS, SEC, and others, depending on the nature of suspected criminal activity. Once you become aware that a federal investigation is underway, the first 48 hours are critical.

The immediate step should be to seek legal counsel from an experienced federal defense attorney who specializes in white-collar crime. Early consultation with such counsel can make or break your case down the line. Counsel will advise on how to respond to requests for information and ensure that any interactions with law enforcement are handled appropriately, minimizing risks.

One of the most critical considerations during this initial phase is whether you might be offered a proffer agreement or “Queen for a Day” letter by federal investigators. Proffer sessions provide limited-use immunity and allow individuals to speak freely about their knowledge without fear of self-incrimination. However, statements made in these sessions can still be used against the individual if they ultimately decide not to cooperate with the government.

Another key consideration is derivative use: information derived from a proffer session or other voluntary disclosures can often be used by federal prosecutors even if the original statement itself cannot. This underscores the importance of having legal representation before making any such statements.

Additionally, law enforcement may seek to invoke Kastigar hearings where they claim that evidence was obtained independently and is thus admissible despite potential contamination from proffer sessions or other voluntary disclosures. Early legal intervention can help prevent these situations by guiding how information is shared with the government.

Finally, 5K1.1 cooperation agreements must be approached carefully under attorney guidance. These agreements are used to reward substantial assistance to authorities in uncovering further crimes and can lead to more lenient sentencing recommendations from prosecutors.

Avoid any direct communication with law enforcement without legal representation. Do not attempt to outmaneuver investigators or make statements without counsel present, as this could undermine your defense later on.

Equally important is the preservation of documents and data relevant to the investigation. This includes emails, text messages, financial records, business papers, and other digital communications. Ensure that all materials are stored securely and documented properly in case they need to be produced or explained at a later date.

In conclusion, knowing you are under federal investigation is daunting but proactive steps can protect your rights and interests. Seek legal counsel immediately, understand the nuances of proffer agreements, derivative use limitations, Kastigar hearings, 5K1.1 cooperation deals, and preserve all relevant documentation meticulously.

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