To get immunity from prosecution, you need a criminal defense attorney to negotiate it with the prosecutor handling the case. Immunity is something the government offers in exchange for testimony or evidence it can’t easily get elsewhere; you can’t demand it, and a judge can’t order it on your own motion. The typical path runs from an attorney’s initial outreach, through a proffer session where prosecutors evaluate what you know, to a written agreement or court order that spells out the protection you receive and what you owe in return.
Who Can Actually Grant Immunity
Only prosecutors can start the process. In federal cases, the U.S. Attorney for the district must request an immunity order from the federal district court, and that request requires prior approval from the Attorney General, the Deputy Attorney General, or a designated senior Justice Department official.1Office of the Law Revision Counsel. 18 U.S. Code 6003 – Court and Grand Jury Proceedings Once the court issues the order and it’s communicated to the witness, the witness can no longer refuse to answer on self-incrimination grounds, and in exchange federal law bars the government from using the compelled testimony or anything derived from it in a later criminal case, except in a prosecution for perjury or false statements.2Office of the Law Revision Counsel. 18 U.S. Code 6002 – Immunity Generally
Not every deal runs through a court order. Prosecutors also offer what practitioners call informal or “pocket” immunity through a letter agreement signed directly between the prosecutor’s office and the defense. These function as contracts, and courts generally enforce them. Informal agreements give both sides more flexibility because no court order is involved, but the terms are only as good as what’s written on the page.
The Negotiation Path, Step by Step
The process starts with your defense attorney contacting the prosecutor’s office. The pitch is straightforward: you have information the government needs, and you’re willing to share it in exchange for protection. Your attorney’s job is to convey that the information is valuable, credible, and unobtainable through other means, without giving away the substance. Prosecutors have no obligation to listen, and they won’t engage unless they believe you can deliver something that advances a significant investigation.
The Proffer Session
If the prosecutor is interested, the next step is usually a proffer session. Before anyone says a word, both sides sign a proffer agreement, sometimes called a “queen for a day” letter. The agreement offers a limited protection: the government cannot use your direct statements from the session as part of its case if it later prosecutes you. It is not immunity, and it does not promise a plea deal.
During the session, you sit down with prosecutors and investigators and answer their questions. Your attorney is present, but the government runs the interview. Prosecutors are evaluating both the quality of your information and whether you’d hold up as a witness. Inconsistencies, evasiveness, or attempts to minimize your own role all count against you.
The Formal Agreement
If the government decides your information is valuable and believes you’re telling the truth, the negotiation moves to a binding written agreement. This document specifies the type of immunity being granted, the scope of the protection, and your obligations. Those obligations almost always include testifying truthfully before a grand jury or at trial, turning over relevant documents or evidence, and cooperating fully as the investigation continues. The agreement may be formalized through a court order under the federal immunity statutes, or it may take the form of a detailed letter signed by both parties.
What the Proffer Session Actually Protects, and What It Doesn’t
This is where people get hurt. A proffer agreement is not immunity, and the gaps in its protection are real.
The biggest one is derivative use. The agreement prevents prosecutors from playing a recording of your statements in their case against you, but it does not stop them from using what they learned to find new evidence. If you name a co-conspirator and investigators go interview that person, and that person then agrees to testify against you, that new testimony is admissible. Your own words led them to the witness who convicts you.
The second problem is impeachment. Most proffer agreements let the government use your statements against you if you later say something inconsistent, whether at trial, in a different proceeding, or through your lawyer’s arguments in court. Memory is imperfect. A detail you recall differently months later can be characterized as an inconsistency, and that opens the door to everything you said in the proffer.
Third, proffer statements can shape your sentence even if they’re never used at trial. Federal sentencing guidelines let courts consider “relevant conduct” when calculating an offense level, and admissions from a proffer can expand that calculation significantly. The agreement protects you from direct use in the prosecution’s case. It provides no protection at sentencing.
Do not participate in a proffer session without an experienced criminal defense attorney who regularly handles federal cases. A poorly managed proffer can leave you worse off than never cooperating at all.
The Two Forms of Immunity You Might Be Offered
Transactional immunity is the broader form. If you receive it, the government cannot prosecute you for any offense connected to the subject of your testimony, even if investigators later develop independent evidence linking you to the crime. Because it gives up so much prosecutorial power, it is uncommon. A handful of states still provide it by statute; the federal system does not use it.
Use and derivative use immunity is the standard in federal cases and in most states. The government cannot use your compelled testimony against you, and it cannot use any evidence that investigators discovered as a result of that testimony. But prosecutors can still charge you for the same crime if they can prove their evidence came from a source completely unconnected to anything you said.3Justia U.S. Supreme Court Center. Kastigar v. United States, 406 U.S. 441 (1972) The Supreme Court held in Kastigar v. United States that this level of protection is enough to replace the Fifth Amendment privilege, because it puts you in essentially the same position as if you had stayed silent.
Practically, use immunity protects your words and everything those words lead to, but it does not make you untouchable. If the FBI was already building a case against you with surveillance footage and cooperating witnesses before you opened your mouth, that evidence remains fair game. If prosecutors do move against you after immunized testimony, your defense can demand a Kastigar hearing, where the government has to prove that every piece of evidence it wants to use came from a legitimate source independent of what you said.
Cooperation Agreements Are Not Immunity
Most people who “cut a deal” don’t get immunity. They enter into cooperation agreements, which are different in kind. In a cooperation agreement you plead guilty to a charge, and in exchange for substantial assistance the prosecutor agrees to recommend a reduced sentence. You still end up with a conviction. In federal court, the government files a 5K1.1 motion asking the judge to depart below the sentencing guidelines, and the size of the reduction depends on how valuable your cooperation turns out to be.
True immunity means no conviction for the covered conduct. That’s a much better outcome, which is exactly why prosecutors rarely offer it. The government prefers cooperation agreements because they still get your testimony while holding a guilty plea as leverage. Immunity deals tend to be reserved for witnesses whose own conduct isn’t serious enough to warrant prosecution, or for cases where the target is so important that prosecutors are willing to let a smaller fish walk to land the bigger one.
The distinction matters because it changes the negotiation. If a prosecutor offers a cooperation agreement when your attorney believes the facts support pushing for immunity, that’s a conversation worth having before you sign anything.
How You Can Lose Immunity
Immunity is not a blank check. It comes with conditions.
The fastest way to lose it is to lie. Every immunity agreement requires complete truthfulness. Perjury under oath carries up to five years in federal prison,4Office of the Law Revision Counsel. 18 U.S. Code 1621 – Perjury Generally and making false statements to federal investigators carries the same maximum.5Office of the Law Revision Counsel. 18 U.S. Code 1001 – Statements or Entries Generally The federal immunity statute itself explicitly carves out perjury and false statements from its protection.2Office of the Law Revision Counsel. 18 U.S. Code 6002 – Immunity Generally Beyond the new criminal exposure, lying breaches the cooperation agreement, which can free prosecutors to use everything you previously told them.
Immunity also has boundaries. It covers the subject matter of your testimony. It does not protect you from prosecution for crimes you commit afterward, and it doesn’t shield conduct unrelated to what you were asked about. Testify about a fraud scheme from last year, then participate in a new one next month, and your agreement covers only the first.
What Happens If You Refuse to Testify After a Court Order
Once a court issues an immunity order, your Fifth Amendment privilege is gone because the order has replaced it with legal protection. If you still refuse, you can be held in civil contempt and confined until you comply or the proceeding ends. Federal law caps this confinement at 18 months, and it can also end sooner if the grand jury’s term expires or the court proceeding concludes.6Office of the Law Revision Counsel. 28 U.S. Code 1826 – Recalcitrant Witnesses A court can also punish refusal as criminal contempt through fines, imprisonment, or both, separate from civil contempt.7Office of the Law Revision Counsel. 18 U.S. Code 401 – Power of Court Civil contempt ends when you agree to testify; criminal contempt is a punishment that stands whether you eventually cooperate or not.