Kastigar Hearings: Preventing the DOJ from Using Your "Immunized" Testimony Against You

A Kastigar hearing is a court proceeding to determine whether the government's evidence is independent of a defendant's immunized testimony.

If prosecutors issued a subpoena for your testimony and promised you immunity in return, this hearing ensures prosecutors don't violate your Fifth Amendment rights by using the testimony you were forced to give.

While "use and derivative-use immunity" offers significant protection, it does not provide an absolute bar against prosecution.

This creates a substantial risk: the government might, intentionally or inadvertently, use information derived from your compelled testimony to build a case against you.

If this happens, a good defense attorney will request a Kastigar hearing requiring the DOJ to prove that none of their evidence against you came from your testimony.

If it did, that evidence must be suppressed--and in some cases, this may even result in a dismissal of the charges.

If you are facing federal charges after providing immunized testimony, you need to hire a skilled federal criminal defense attorney immediately to make sure your Constitutional rights remain protected. Call Eisner Gorin LLP today at (818) 781-1570 or contact us here.

What Is a Kastigar Hearing?

A Kastigar hearing is a pretrial hearing where the prosecution must prove to a judge that all evidence it intends to use against a defendant comes from sources completely independent of the defendant's earlier immunized testimony.

This hearing derives its name from the landmark U.S. Supreme Court case Kastigar v. United States (1972). The Court held that the government may compel a witness to testify, even if the witness objects under the Fifth Amendment, provided the immunity fully protects them from self-incrimination.

This created "use and derivative-use immunity." Under this standard, the government cannot use the specific testimony (use) or any evidence discovered from leads provided by that testimony (derivative-use) in a criminal case against the witness.

This is very different from "transactional immunity," which completely protects a person from being prosecuted for anything they talk about.

Kastigar hearings are needed because the use of immunity doesn't stop the government from prosecuting the person for the same crimes. However, the government must prove that its evidence wasn't influenced by anything the person said.

When Would an Attorney Request a Kastigar Hearing?

An attorney requests a Kastigar hearing when their client (the defendant) is charged with a crime related to testimony they were previously required to give prosecutors under a pledge of immunity.

Because the testimony was given under immunity, using that testimony as evidence later on violates the defendant's Fifth Amendment Rights.

The Kastigar hearing places the burden of proof on prosecutors to show they are not using that testimony as evidence, either directly or indirectly.

This hearing is sometimes called a "taint" hearing because the defendant claims the prosecution's case is "tainted" by the defendant's immunized statements.

What Must the Government Prove at a Kastigar Hearing?

At a Kastigar hearing, the government bears a heavy and affirmative burden to demonstrate, by a preponderance of the evidence, that its case is based solely on legitimate sources independent of the immunized testimony.

The prosecutor cannot simply deny the use of the testimony. Instead, they must affirmatively prove the independent origins of their evidence. This involves showing a clear, untainted path for every piece of evidence they intend to present.

This burden applies to:

Witness testimony: Showing that witnesses knew the facts before the immunized testimony was given.
Documents: Proving that subpoenas for records were issued based on independent leads.
Physical evidence: Demonstrating that the location of evidence was known prior to the testimony.

Direct or Indirect Use

It's not enough for the prosecution simply to prove no "direct use" of the immunized testimony (e.g., presenting it to the grand jury to procure an indictment).

They must also show no "indirect" or "derivative" use of the testimony. This is more complex and often where the battle is fought.

The government must prove it did not use the testimony for:

Focusing an investigation on the defendant that was previously aimless.
Deciding to initiate a prosecution they otherwise wouldn't have brought.
Shaping interrogation questions for other witnesses.
Interpreting the significance of other evidence that was previously misunderstood.

What Is the "Walled Off" or "Taint Team" Strategy?

The "taint team" strategy is a process that prosecutors typically use to meet the burden of proof that the evidence against the defendant was in no way related to their earlier testimony.

Prosecutors often use a "taint team" to review immunized testimony and filter out privileged information.

A separate "clean team" of prosecutors and agents, isolated from the taint team's work, handles the investigation and prosecution.

During the hearing, the court will examine the effectiveness of this separation, looking for any breaches, such as communication between the teams or the sharing of files. Any lapse could result in the suppression of evidence.

Related Federal Crimes and Legal Issues

Kastigar hearings often arise in complex federal investigations involving fraud, corruption, or conspiracy. In these cases, witnesses may be compelled to testify under immunity before later becoming defendants themselves.

The following offenses commonly appear in cases where a Kastigar hearing may be necessary.

Perjury – 18 U.S.C. § 1621

Perjury occurs when someone knowingly makes a false statement under oath during a legal proceeding, including testimony before a grand jury or in federal court. If a witness receives immunity and later provides false testimony, prosecutors may pursue perjury charges even though the testimony itself cannot be used to prosecute the underlying offense.

False Statements – 18 U.S.C. § 1001

Federal law makes it a crime to knowingly provide false or misleading statements to federal investigators or agencies. This charge frequently appears in investigations conducted by agencies such as the FBI, IRS, or Department of Justice. Even when testimony is given under immunity, false statements may still lead to prosecution.

Obstruction of Justice – 18 U.S.C. §§ 1503 and 1512

Obstruction of justice involves interfering with a federal investigation or court proceeding. This may include destroying evidence, influencing witnesses, or attempting to hinder the administration of justice. Immunized testimony may relate to obstruction allegations if prosecutors believe a witness attempted to conceal information during an investigation.

Conspiracy – 18 U.S.C. § 371

Federal conspiracy law makes it illegal for two or more people to agree to commit a federal crime and take any step toward completing that offense. Conspiracy charges frequently arise in large federal investigations where witnesses provide testimony about the actions of multiple individuals.

Wire Fraud – 18 U.S.C. § 1343

Wire fraud involves using electronic communications such as phone calls, emails, or internet transactions to carry out a fraudulent scheme. Federal fraud investigations often involve multiple witnesses and extensive testimony, which may later lead to Kastigar issues if immunity was granted during earlier stages of the investigation.

Mail Fraud – 18 U.S.C. § 1341

Mail fraud occurs when someone uses the U.S. postal service or commercial delivery carriers to further a fraudulent scheme. Similar to wire fraud cases, mail fraud investigations frequently involve grand jury testimony that could later become the subject of a Kastigar hearing.

RICO Violations – 18 U.S.C. § 1962

The Racketeer Influenced and Corrupt Organizations Act (RICO) allows federal prosecutors to charge individuals who participate in organized criminal enterprises. RICO cases often involve large investigations with numerous witnesses, making immunity agreements and Kastigar hearings particularly relevant.

Frequently Asked Questions

What is a Kastigar hearing in federal court?

A Kastigar hearing is a pretrial hearing where the government must prove that the evidence it intends to use against a defendant was obtained independently of any immunized testimony previously given by that defendant.

The hearing exists to protect a person's Fifth Amendment right against self-incrimination. If the defendant was compelled to testify under immunity, prosecutors are prohibited from using that testimony—or any evidence derived from it—against the defendant in a criminal case.

Why are Kastigar hearings important in federal investigations?

Kastigar hearings ensure that prosecutors do not build a criminal case using a defendant's own compelled statements. When testimony is given under immunity, the government must prove that its investigation relied entirely on independent sources.

Without this safeguard, prosecutors could indirectly rely on immunized testimony to develop leads, question witnesses, or gather evidence that would otherwise not exist.

What happens during a Kastigar hearing?

During a Kastigar hearing, federal prosecutors must present evidence showing that their investigation was not influenced by the defendant's immunized testimony. This often includes:

witness testimony explaining when investigators learned certain facts
documents or records obtained before the immunized testimony was given
investigative timelines showing the origin of evidence
proof that prosecutors and investigators were not exposed to the testimony

Defense attorneys may cross-examine investigators and prosecutors to identify any connection between the testimony and the evidence used in the case.

What is use and derivative-use immunity?

Use and derivative-use immunity means the government cannot use a witness's compelled testimony or any evidence derived from that testimony against them in a criminal case.

However, this type of immunity does not completely prevent prosecution. Prosecutors may still pursue criminal charges if they can prove that their evidence came from sources entirely independent of the immunized testimony.

What is the difference between use immunity and transactional immunity?

Use and derivative-use immunity only prevent the government from using the immunized testimony or information derived from it.

Transactional immunity, on the other hand, completely protects a witness from prosecution for the offenses discussed in their testimony. Federal prosecutors rarely grant transactional immunity because it prevents them from filing charges entirely.

Can a criminal case be dismissed after a Kastigar hearing?

Yes. If the court finds that prosecutors relied on immunized testimony or evidence derived from that testimony, the court may suppress the tainted evidence.

In serious cases where the investigation is heavily influenced by the immunized testimony, the judge may dismiss the charges entirely because the prosecution cannot proceed without violating the defendant's constitutional rights.

What is a “taint team” in a federal investigation?

A taint team, sometimes called a filter team, is a group of prosecutors and investigators assigned to review privileged or immunized material. Their job is to separate protected information from evidence that investigators can legally use.

The main prosecution team is supposed to remain isolated from the immunized testimony so that their investigation is not influenced by it.

When should a defense attorney request a Kastigar hearing?

A defense attorney typically requests a Kastigar hearing when:

a defendant previously testified under immunity
the government later files criminal charges related to that testimony
there is reason to believe the investigation relied on information obtained from the immunized statements

This hearing forces prosecutors to demonstrate that their case was developed without using the defendant's compelled testimony.

Can immunized testimony still lead to criminal charges?

Yes. Immunized testimony does not automatically prevent criminal prosecution. It only prevents prosecutors from using the testimony or evidence derived from it.

If prosecutors can prove that their evidence was obtained independently, they may still proceed with the case.

Why is legal representation important in Kastigar hearing cases?

Kastigar hearings involve complex constitutional issues and detailed analysis of investigative timelines, witness statements, and evidence collection.

A skilled federal criminal defense attorney can challenge the government's claims of independent evidence, expose investigative overlap, and argue for suppression of evidence or dismissal of charges when constitutional violations occur.

What Are the Possible Outcomes of a Kastigar Hearing?

The outcome of a Kastigar hearing can range from the prosecution being allowed to proceed to the suppression of specific evidence to the complete dismissal of the criminal charges.

Once the hearing is complete, the court will make one of three rulings:

Prosecution Proceeds: The court finds the government has met its heavy burden and proven all evidence is from legitimate, independent sources. The case moves forward to trial, but the defense has now seen a preview of the government's entire case.
Suppression of Tainted Evidence: The court finds that specific pieces of evidence—such as a key witness or a crucial financial document—were derived from the immunized testimony. This evidence is suppressed and cannot be used by the prosecution, weakening their case.
Dismissal of Charges: In cases of pervasive taint, where the immunized testimony has so thoroughly infected the investigation that an untainted prosecution is impossible, the court may dismiss the indictment entirely.

How Can a Defense Attorney Challenge the Government's Evidence in a Kastigar Hearing?

A good federal criminal defense attorney challenges the government's claims of independence by cross-examining federal agents and prosecutors and presenting evidence to show that the prosecution's case was, in fact, tainted by the immunized testimony.

At Eisner Gorin LLP, we use a multifaceted approach during Kastigar hearings:

Challenging Procedural Safeguards

The first line of defense is scrutinizing the "wall" between the taint team and the prosecution team for any leaks or breaches. We investigate whether any member of the prosecution team was exposed to the immunized testimony, even inadvertently.

This exposure can happen in subtle ways:

Reading a news report that quotes the testimony.
Overhearing a conversation between agents.
Reviewing a memo that implicitly relies on the immunized information.

If we can prove that the "clean team" was exposed, the burden shifts back to the government to prove that this exposure did not influence their trial strategy.

Exposing Tainted Evidence and Witnesses

We rigorously examine the timeline of the investigation to find causal links between your testimony and the evidence against you.

Witness Exposure: Did witnesses who will testify against the defendant have their memories refreshed or influenced by reading transcripts or summaries of the immunized testimony? Courts have held that if a witness's testimony is shaped by their exposure to immunized statements, that testimony may be suppressed.
Investigative Leads: Can the defense show that an investigative lead that produced key evidence originated from the immunized testimony?

Related Case Study

We recently fought to have key prosecution evidence dismissed, resulting in our client being placed on probation.

In summary, a Kastigar hearing is a fundamental safeguard for your Fifth Amendment rights. It forces the government to prove that its case against you was not built using your own compelled words.

The process involves a heavy burden on the prosecution and provides a critical opportunity for a skilled defense to challenge the very foundation of the government's case.

Navigating the complexities of immunized testimony and a subsequent federal prosecution requires deep legal knowledge. The stakes are incredibly high, and a successful defense often hinges on meticulously dissecting the government's investigation for any sign of taint.

If you are concerned that the government may be using your immunized testimony against you, do not wait. Protect your future by hiring skilled legal counsel right away.

At Eisner Gorin LLP, our federal criminal defense attorneys are highly skilled and experienced in enforcing Constitutional protections, including providing effective defense strategies such as a Kastigar hearing.

Call our offices at (818) 781-1570 or contact us here.

Kastigar Hearings