Federal Immunity Agreements: Use vs Derivative Use

When federal prosecutors offer you immunity, they make it sound like protection. A shield. A way out. But immunity agreements in the federal system are confession extraction tools disguised as safety. Use immunity doesn't protect you from prosecution - it only blocks your exact words from being used against you in court. Everything you lead investigators to becomes fair game for "independent" evidence gathering. And here's what they don't tell you: prosecutors document their existing evidence before your proffer specifically so they can later claim they found everything "independently." The burden to prove that independence is only 50.1% - preponderance of the evidence, not beyond a reasonable doubt. You confess everything, they hunt based on your roadmap, then they prosecute you anyway. The system isn't designed to protect cooperating witnesses. Its designed to extract testimony while preserving prosecution options.

This is what defense attorneys at Spodek Law Group see constantly - clients who think immunity means safety, then discover it means confession with a loophole. Todd Spodek has spent years navigating the gap between what immunity agreements promise and what they actually deliver. The federal system eliminated the immunity that genuinely protects you - transactional immunity, which blocks all prosecution for the crimes you testify about. Instead, federal prosecutors offer only use and derivative use immunity under 18 U.S.C. § 6002. The difference isn't technical. Its the difference between actual protection and a trap that requires you to waive your Fifth Amendment right, speak, then hope prosecutors can't prove they found the same evidence a different way. Spoiler: they can, and they document everything to prove it.

The most important thing to understand about federal immunity is that normal protection means staying silent. Immunity "protection" requires you to do the opposite - confess everything, then rely on a legal standard that's stacked against you. If you're staring at a target letter, a grand jury subpoena, or a prosecutor's offer to "talk," you need to understand what immunity actually is before you say a single word. Because once you waive the Fifth Amendment and start talking, there's no taking it back. And the version of your story that matters isn't the one you tell - its the one government agents write down.

The Confession You Weren't Expecting to Make

Here's the thing nobody explains clearly: accepting immunity means waiving your Fifth Amendment right against self-incrimination. You cant take the Fifth once you've been granted immunity. The entire point of immunity, from the prosecution's perspective, is to remove your ability to remain silent. They need your testimony - for a grand jury, for trial, to build a case against someone higher up the chain - and your Fifth Amendment right is standing in there way. Immunity is the legal tool that forces you to speak.

Normal protection works like this: you stay silent, invoke the Fifth, force prosecutors to build their case without your help. Immunity flips that completely. You must speak. You must answer questions. You must provide testimony. And if you refuse, you can be held in contempt and jailed until you comply. This is "protection" that requires confession as the entry fee.

The federal system dosent offer transactional immunity - the kind that actually protects you. Transactional immunity means you can't be prosecuted for any crimes related to your testimony. You testify about the bank fraud? You're immune from bank fraud charges. Period. Full stop. Thats real protection. But federal prosecutors havent used transactional immunity in decades. They eliminated it on purpose.

What they offer instead is use and derivative use immunity under 18 U.S.C. § 6002. The statute says prosecutors cant use your compelled testimony against you, and they can't use evidence "directly or indirectly derived" from your testimony. Sounds protective. Until you realize what "derived from" actually means in practice. The statute lets them prosecute you as long as they can show there evidence came from a "legitimate source wholly independent" of your immunized testimony. And the burden to prove that? Only preponderance of the evidence. Fifty point one percent confidence. Not beyond a reasonable doubt.

So you waive your Fifth Amendment right - the most powerful protection you have - in exchange for a promise that only blocks the direct use of your words. Everything else? Fair game, as long as they can document it came from somewhere else. And they will.

"Queen for a Day" - And Defendant for Life

Prosecutors call proffer agreements "Queen for a Day" letters. Sounds fancy. Sounds like special treatment. But the nickname tells you exactly how long your protection lasts: one day. The duration of the interview. Thats it. You're royalty while your speaking, then the hunt begins.

A proffer agreement is the weakest form of immunity. Its not a plea deal. Its not a promise you wont be prosecuted. Its a written agreement that says: "You talk, we wont use your exact words against you in our case-in-chief, but we can use them for impeachment if you testify differently later, and we can use anything we find based on the leads you give us." The protection is so narrow it barely exists.

Here's how it works in practice. You sit down with federal prosecutors and agents. Your stressed, scared, trying to remember events from months or years ago. They ask questions. You answer. They take notes. Those notes become "your version" of events - even though its there interpretation of what you said, written in there words, reflecting there understanding. And later, if you testify at trial and your testimony differs even slightly from those notes, prosecutors can use your proffer statements to impeach you. They'll stand up in court and say, "But you told us something different back in the proffer." Your credibility evaporates. The jury thinks your lying. And the version there comparing to isnt even your actual words - its the government agents' summary of what they think you said.

The moment the session ends, prosecutors take everything you told them and use it as a roadmap:

• You mentioned a meeting in January 2023? They pull phone records for January 2023.
• You referenced a specific email? They subpoena email servers.
• You named a cooperating witness? They interview that person.

You just gave them the treasure map, and now there digging.

And heres the kicker: if they find evidence based on your leads, they document it as coming from an "independent source." They dont write, "We found this because the defendant told us where to look." They write, "We obtained phone records pursuant to subpoena" or "We interviewed Witness A who independently corroborated." By the time they indict you, there evidence looks clean. Independent. Untainted by your immunized testimony. And under Kastigar v. United States, thats all they need.

18 U.S.C. § 6002 is the federal statute that authorizes use and derivative use immunity. Notice its Section 6002, not Section 6001. The feds could offer broader protection, but they choose not to. They want testimony and prosecution options. Use immunity gives them both. You confess everything, they hunt based on what you said, then they prove in court that they "found" the evidence independently. Your the queen for a day. Then your a defendant for life.

The Independent Source Loophole

The entire federal immunity system rests on one concept: independent source. Prosecutors can use evidence against you as long as its derived from a source "wholly independent" of your immunized testimony. This sounds like a real protection. It isnt. Its a loophole big enough to drive a prosecution through, and prosecutors prepare to exploit it before you ever speak.

Heres what "independent source" actually means in practice. Before your proffer session, prosecutors and agents create detailed evidence summaries. They document every piece of evidence they already have:

• Witness statements
• Surveillance footage
• Financial records
• Emails
• Phone records
• Physical evidence

They note the dates they obtained each piece of evidence and the sources. This documentation serves one purpose: to later prove that they had evidence before you spoke, or that they obtained evidence from sources unrelated to your testimony.

You sit down for your proffer. You tell them about the wire transfers. You mention the offshore accounts. You name the other participants. You describe the timeline. And the entire time, there comparing what your saying to what they already have. When you mention something they didnt know, they dont write, "Learned this from defendant's proffer." They write, "Will investigate through independent means."

After your proffer, they follow the leads you gave them. But they document those leads as coming from somewhere else. You mentioned a meeting in Miami? They subpoena hotel records and credit card statements. When they find the evidence, they document it as coming from "financial institution records obtained via subpoena" - not from "defendant's proffer disclosure." You gave them the roadmap, but they document it as if they found the destination on there own.

The Supreme Court blessed this system in Kastigar v. United States, 406 U.S. 441 (1972). The Court said use and derivative use immunity is constitutional because it shifts the burden to prosecutors. If they want to prosecute you after you've given immunized testimony, they have to prove affirmatively that all evidence they plan to use came from legitimate sources wholly independent of your compelled testimony. Sounds protective. Except the burden is only preponderance of the evidence - 50.1% confidence. Not beyond a reasonable doubt. Not clear and convincing. Just more likely than not.

And prosecutors meet that burden with the evidence timelines they created before your proffer. The court holds a pre-trial Kastigar hearing. Prosecutors present there evidence summary showing they had surveillance footage before your proffer. They show they subpoenaed bank records based on "ongoing investigation," not your disclosure. The burden is low, and they've prepared to meet it. The Kastigar hearing is rigged before it starts, because they documented everything specifically to win it.

Surveillance they already had, informants you didnt know about, documents they already seized - all of it qualifies as "independent." Proving independence is easy when you document everything first. And you just gave them the complete story, the timeline, the participants, the evidence locations. They dont need to use your words in court. They have the map you drew, and they followed it to the evidence, then documented it as if they found it alone.

The 50.1% Shield vs The 99.9% Sword

The entire immunity system rests on a burden of proof imbalance that nobody talks about. When prosecutors want to convict you at trial, they need to prove guilt beyond a reasonable doubt - somewhere north of 99% certainty. When they want to prove they can use evidence against you despite immunity, they only need preponderance of the evidence - 50.1%. Thats the gap between your protection and there prosecution power. And its massive.

Kastigar v. United States supposedly protects witnesses by shifting the burden. The prosecution has to prove affirmatively that evidence is derived from legitimate sources wholly independent of immunized testimony. That sounds like a heavy burden. Its not. The standard is preponderance of the evidence - more likely than not. If the judge thinks theres a 51% chance the evidence came from independent sources, the evidence comes in. Your testimony gets used against you, just indirectly.

You proffer. You tell them everything. They follow your leads and gather evidence. You get indicted. At the Kastigar hearing, they present there evidence timeline showing they had some evidence before your proffer. They show they obtained other evidence via subpoenas and witness interviews after your proffer. They argue the investigation "would have led" to the same evidence even without your testimony. The judge decides: is it more likely than not that this evidence came from independent sources?

If the answer is yes - even barely yes, even 50.1% yes - the evidence is admissible. You get prosecuted using evidence you led them to, and the only thing protecting you is a burden of proof that's lower than the burden for a civil lawsuit. Your confessing to a crime, waiving your Fifth Amendment protection, and betting everything on a 50.1% burden that prosecutors prepared to meet.

Meanwhile, to convict you at trial, prosecutors need proof beyond a reasonable doubt. The jury needs to be virtually certain - 99%+. So the burden to use evidence against you is 50.1%, but the burden to convict you is 99%+. The shield is tissue paper. The sword is steel.

The Traps Nobody Mentions

Even if you understand the independent source loophole, even if you know about the 50.1% burden, there are traps in modern proffer agreements that defense attorneys call "the fine print disasters."

First trap: the inconsistency exception

Your proffer statements cant be used against you in the prosecution's case-in-chief. But they can be used for impeachment if you testify at trial and your testimony is inconsistent with what you said in the proffer. Sounds fair - if you lie at trial, prosecutors can call you out. Except "inconsistent" doesnt mean lying. It means any difference:

• You misremember a date during the proffer? Inconsistent.
• You describe an event slightly differently six months later on the witness stand? Inconsistent.
• The stress of trial makes you recall details in a different order? Inconsistent.

And the version your being compared to isnt your actual words - its the government agents' written summary of what they think you meant.

Honest mistakes become "lies." Your proffer statement gets read to the jury. Your credibility evaporates. And the jury hears your confession - because thats what a proffer is - even though it was supposedly "protected."

Second trap: the cross-examination exception

Modern proffer agreements have gotten worse in recent years. Many now include language saying your proffer statements can be used against you if your defense - including your lawyers cross-examination questions - is inconsistent with what you said. Read that again. If your defense attorney asks a government witness a question that contradicts your proffer, prosecutors can introduce your proffer statements.

This exception effectively eliminates your right to present a defense. Your lawyer wants to cross-examine the lead agent about surveillance gaps? If that theory contradicts anything you said in your proffer, the proffer comes in. You confessed during the proffer because you thought it was protected, and now your own lawyers defense strategy makes it admissible.

Third trap: the cascade

These traps compound. You misremember a date during your proffer because your stressed and the event was 18 months ago - honest mistake. Later, prosecutors find evidence showing a different date. Now your proffer contains a "lie." At trial, you testify truthfully based on what you actually remember. It contradicts the agents' written version of what you said. Prosecutors impeach you with the proffer. The jury hears you made a "false statement" in your proffer, then changed your story at trial. Your credibility is destroyed. The jury thinks your lying even though you've been truthful the entire time - you just made an honest mistake under pressure that became permanent when an agent wrote it down wrong.

When Immunity Backfires - Real Cases

Bill Cosby's Immunity Boomerang

Bill Cosby's case is the clearest example of immunity turning into a weapon. In 2005, a Pennsylvania prosecutor named Bruce Castor decided he couldnt win a criminal conviction against Cosby for sexual assault. So he offered Cosby immunity to testify in the victims civil lawsuit. Cosby accepted. He gave a deposition. He admitted giving Quaaludes to women. He admitted sexual contact. All under immunity.

Then a new prosecutor took office. Kevin Steele decided to prosecute Cosby criminally using the very testimony Cosby gave under immunity. Cosby argued he'd been promised immunity - he never would have testified without it. Prosecutors argued the immunity wasnt properly formalized. The court sided with prosecutors. Cosby was convicted and sentenced to prison.

He spent nearly three years imprisoned before the Pennsylvania Supreme Court overturned the conviction, finding that the immunity agreement had been valid and using his testimony violated due process. But the damage was done. Cosby gave immunized testimony thinking he was protected, got prosecuted anyway, got convicted, and spent years in prison before being freed on appeal. The immunity boomerang - you throw it thinking its protection, and it comes back to destroy you.

Ghislaine Maxwell's 2024-2025 Proffer

Ghislaine Maxwell's 2024-2025 proffer immunity shows the same dynamic in current federal practice. Maxwell is already convicted and serving her sentence for sex trafficking related to Jeffrey Epstein. In late 2024 and early 2025, the DOJ offered her proffer immunity to discuss "about 100 different people" connected to Epsteins network. The immunity doesnt undo her conviction. It doesnt reduce her sentence. It only protects her statements during those specific DOJ interviews from being used against her in future prosecutions.

Maxwells immunity is use immunity - the narrow kind. She talks, they cant use her exact words against her, but they can use anything they find based on her leads. And her existing conviction stands regardless. The DOJ gets information about 100 people, Maxwell gets limited protection that only applies to those specific interview sessions.

When to Accept, When to Refuse

So when does immunity make sense? Accept immunity or a proffer if: your facing imminent indictment, you need a plea deal or cooperation agreement, and you cant get either without first providing information. In white-collar federal cases, prosecutors typically wont offer a plea deal until you proffer. They need to know what you know, what you can offer, and whether your testimony helps them. If your realistically looking at serious charges and your only path to a reduced sentence is cooperation, you may have no choice but to proffer.

But - and this is critical - you should only proffer if your genuinely prepared to cooperate fully, tell the complete truth, and accept the risks. Proffers make sense as the first step toward a cooperation deal, not as a way to "test the waters" or "see what happens."

Refuse immunity and stay silent if: your planning to fight the case and go to trial. If you genuinely believe your innocent, or you think the government cant prove its case beyond a reasonable doubt, proffers make no sense. Your giving them your version of events, your timeline, your explanations - and none of that helps you at trial. It only gives them ammunition.

Defense attorneys are clear about this: if you plan on fighting the case and going to trial, it would make no sense to tell the government anything with or without a proffer agreement. Your Fifth Amendment right to remain silent is your most powerful protection. Immunity requires you to waive it. If your strategy is to force the government to prove there case without your help, dont help them by confessing under immunity.

What Your Attorney Should Tell You

Federal prosecutors present immunity as an opportunity. A chance to help yourself by helping them. A path to leniency. What they dont emphasize are the traps, the exceptions, the ways immunity can backfire and become evidence against you.

Prosecutors wont tell you that they document existing evidence before your proffer specifically to later prove independent source. They wont tell you that the burden to prove independence is only 50.1%. They wont tell you that modern proffer agreements include cross-examination exceptions that can eliminate your ability to defend yourself. They wont tell you that "inconsistent" means any difference, not just lies, and that the version your being compared to is the agents' written summary, not your actual words.

What they will tell you:

• "We're offering you a chance to help yourself."
• "Cooperation matters at sentencing."
• "We need to hear your side of the story."

All true. But incomplete. Cooperation does matter at sentencing - if you plead guilty and testify as a government witness. They do need to hear your side - because it helps them build there case. It is an opportunity - for them to extract testimony while keeping prosecution options open.

Experienced federal criminal defense attorneys tell clients the full picture. Immunity agreements are tools. They can be valuable if used correctly as part of a cooperation strategy. They can be catastrophic if accepted blindly, thinking they provide protection when they actually require confession. The decision to accept or refuse immunity is one of the most important decisions in a federal criminal case.

If your facing a federal investigation, if prosecutors have mentioned immunity, if your received a target letter or grand jury subpoena, you need an attorney who understands how immunity actually works in practice, not in theory. Spodek Law Group has defended clients in federal criminal cases across the country. We know how prosecutors use immunity to extract testimony. We know the traps in proffer agreements. We know when cooperation makes sense and when silence is stronger.

Call Spodek Law Group at 212-300-5196. Before you accept immunity, before you sit down for a proffer, before you waive your Fifth Amendment right, understand what your actually agreeing to. Because immunity isnt protection. Its confession with a 50.1% shield. And once you waive the Fifth and start talking, theres no taking it back. Your words - or rather, the government agents' version of your words - become permanent. Make sure you understand the trade your making before you make it. Because prosecutors want your testimony. Whether immunity actually protects you is a different question entirely.