New York City Federal Kastigar Hearing Lawyer

A federal grand jury subpoena arrives, and the government offers immunity in exchange for testimony. What sounds like a reprieve can become a trap. When prosecutors grant immunity and then later claim they built their case against you using independent evidence, the battle over whether they actually honored that promise is fought at a New York City federal Kastigar hearing lawyer‘s most consequential stage. These hearings determine whether the government has truly kept its side of the immunity bargain or whether it has, deliberately or not, used compelled testimony to construct the very prosecution it was forbidden from building.

Kastigar hearings take their name from the 1972 Supreme Court decision that defines the outer limits of use and derivative use immunity. When a witness is granted immunity under federal law and compelled to testify, prosecutors bear the burden at a subsequent Kastigar hearing of demonstrating that every piece of evidence they intend to use at trial was derived from a source entirely independent of the immunized testimony. This is not a light burden. In practice, it requires the government to trace the origin of its evidence with specificity, witness by witness, document by document. A failure to satisfy that burden means charges must be dismissed or evidence must be suppressed. The stakes of getting the hearing right, on both sides, could not be higher.

Federal courts in the Southern and Eastern Districts of New York have been the venue for some of the most intensely litigated Kastigar proceedings in the country. New York federal prosecutors operate at the most sophisticated level of the profession, and any challenge to their immunity compliance requires a defense attorney who understands grand jury practice, the mechanics of complex federal investigations, and the procedural architecture of these hearings inside and out.

What a Kastigar Hearing Actually Demands From Defense Counsel

The hearing itself is adversarial litigation within litigation. It typically occurs after an indictment has been returned and before trial, and it functions as a mini-evidentiary proceeding in which the government must affirmatively prove the independent source of its evidence. Defense counsel’s role is not simply to sit back and watch the government fail. Effective advocacy at a Kastigar hearing requires exhaustive pre-hearing discovery, careful analysis of grand jury transcripts, FBI reports, and agent notes to map the chronological development of the government’s case before immunized testimony was given and after. If the investigation’s trajectory shifted, expanded, or accelerated after the compelled testimony, that is exactly the kind of derivative use that Kastigar prohibits.

Preparation for these hearings demands that counsel understand the full scope of the original investigation, the contents of the immunized testimony itself, and the government’s theory of how its evidence was gathered independently. Cross-examining federal agents and prosecutors’ witnesses at a Kastigar hearing is a distinctive skill. It is not the cross-examination of a fact witness at trial. It requires an attorney who knows what questions reveal the seams in the government’s independent source narrative, where timelines do not align, and where agent conduct suggests that compelled disclosures drove investigative decisions that would not otherwise have been made.

The Range of Kastigar Challenges That Arise in Federal Courts

• Use immunity versus transactional immunity: Federal law provides use and derivative use immunity, not transactional immunity. Understanding what the government is actually prohibited from doing, and what it is still permitted to pursue, shapes the entire defense strategy at a Kastigar hearing in the Southern or Eastern District of New York.
• Derivative use contamination: The most common Kastigar challenge involves the government’s use of leads, witnesses, or investigative directions that flowed from immunized testimony, even if the government did not directly introduce that testimony as evidence. Tracing how an investigation developed is the heart of this challenge.
• Grand jury exposure: When immunized witnesses testify before a grand jury and additional witnesses or evidence are then subpoenaed based on what was learned, the chain of derivative use can run through the entire indictment. Courts in the Second Circuit have addressed the scope of this problem in significant opinions that govern practice in New York federal courts.
• State and federal immunity overlap: When a witness has provided immunized testimony in a state proceeding and is later prosecuted federally, or vice versa, questions arise about whether federal prosecutors were exposed to state immunized testimony and whether that exposure tainted the federal investigation.
• Proffer agreement distinctions: Proffer agreements are not immunity grants, but the line between proffer use limitations and Kastigar protections is frequently litigated. Clients who participated in proffers and later face prosecution need counsel who understands where the proffer agreement ends and the constitutional protection begins.
• Witness cooperation and compelled testimony interaction: In multi-defendant cases, when one target receives immunity and testifies, other defendants may have independent Kastigar claims if the government used what it learned from that cooperating witness to build its case against them.
• Timing and investigative taint: Courts analyze when the government knew certain facts relative to when immunized testimony was given. A Kastigar challenge is strengthened where the government’s knowledge of key facts appears to have expanded immediately following compelled testimony in ways that cannot be explained by prior independent investigation.

How These Hearings Unfold in the Southern and Eastern Districts of New York

Federal Kastigar hearings in New York are conducted before a district court judge, most commonly in the Daniel Patrick Moynihan United States Courthouse at 500 Pearl Street in Manhattan for SDNY cases, and at the Theodore Roosevelt United States Courthouse at 225 Cadman Plaza East in Brooklyn for EDNY matters. Judges in both districts approach these hearings with varying degrees of rigor, and knowing a particular judge’s expectations for how the government must present its independent source evidence is a practical advantage that comes with experience in these courts.

The hearing begins after defense counsel files a motion challenging the government’s compliance with its Kastigar obligations. The government then responds with its proffer of independent sources, often supported by agent affidavits. The court may then schedule the hearing itself, at which agents and supervisors testify about the investigation’s development. Defense counsel’s pre-hearing discovery motions are critical because the government’s obligation to disclose the basis for its independent source claim is not unlimited, and courts must be pressed to require disclosure that is actually sufficient for effective cross-examination.

One of the most important things to understand is that the defense does not bear the burden of proving taint. The government bears the burden of proving cleanliness. That structural advantage is only captured, however, when defense counsel has done the investigative and analytical work necessary to challenge the government’s account with specificity. A vague claim that “the government must have used my testimony” is not enough. The challenge must be precise, grounded in the documented timeline of the investigation, and tied to specific investigative steps that followed immunized disclosures.

Why Jason Goldman’s Background Makes a Difference in Kastigar Proceedings

Jason Goldman began his legal career as a Brooklyn prosecutor, working at the Kings County District Attorney’s office before transitioning to private defense. That prosecutorial foundation provides a perspective that is genuinely rare in Kastigar litigation. Mr. Goldman understands how investigations are actually constructed, how agents decide who to call next, how grand jury strategy develops, and where the pressure points are in an investigation that might reveal derivative use. He knows, from the inside, what it looks like when an investigation changed course because of something a witness said, and he knows how to surface that in cross-examination.

Having tried more than 25 cases to verdict in state and federal courts, Mr. Goldman brings courtroom fluency to what are often technically dense proceedings. A Kastigar hearing requires an attorney who can read a courtroom, manage the pacing of cross-examination, and make the legal argument compelling to a federal judge who has read hundreds of government briefs. His representation spans all phases of federal criminal litigation, from pre-arrest investigations through trials and appellate practice, which means he is positioned to challenge Kastigar compliance as part of a larger, coherent defense strategy rather than as an isolated procedural motion.

Mr. Goldman has been described in press coverage as high-powered and brilliant, and his practice has included representation of corporate executives, professionals, and public figures across New York and beyond. His membership in the National Association of Criminal Defense Lawyers and the New York State Association of Criminal Defense Lawyers, along with his role on the Criminal Courts Committee of the New York City Bar Association, reflects active engagement with the development of criminal defense practice at the highest level. For a proceeding as legally precise as a Kastigar hearing, that depth of engagement with federal criminal practice is not incidental. It is the foundation of an effective challenge.

Questions Clients Ask About Federal Kastigar Hearings

What exactly does “use and derivative use immunity” protect against?

Use and derivative use immunity means the government cannot use your immunized testimony against you directly, and it also cannot use any evidence it obtained because of leads, witnesses, or investigative directions that stemmed from your testimony. If prosecutors learned something from what you said that led them to discover a document, a witness, or a piece of evidence they did not know about before, they cannot use that evidence against you either. The protection is broad, but it requires careful enforcement.

Does immunity mean I cannot be prosecuted at all?

No. Immunity under federal law does not prevent prosecution. It prevents the government from using your compelled testimony or evidence derived from it against you. If the government can demonstrate that it had the evidence to prosecute you entirely from sources that existed before or independent of your immunized cooperation, prosecution remains possible. The Kastigar hearing is where that boundary is enforced.

When does a Kastigar hearing happen in a federal case?

Typically, a Kastigar hearing is initiated by defense motion after indictment and before trial. The motion puts the government on notice that the defendant is challenging its compliance with immunity obligations. The court then determines whether to hold an evidentiary hearing, and if so, schedules it as a pretrial matter. In complex cases, the hearing can span multiple days and involve substantial documentary evidence alongside witness testimony.

What happens if the government fails to satisfy its Kastigar burden?

If the court finds that the government has used immunized testimony or evidence derived from it, the remedy depends on the extent of the violation. A court may suppress specific items of evidence, dismiss individual counts of an indictment, or in cases where the taint is pervasive, dismiss the indictment entirely. The appropriate remedy is determined by the court based on the scope of the constitutional violation found.

Can I raise a Kastigar challenge if I cooperated in a state investigation and am now being federally prosecuted?

Yes. When immunized testimony is given in a state proceeding and federal prosecutors subsequently bring charges, a Kastigar-type analysis applies, though the precise framework depends on whether and how federal agents were exposed to the state testimony and whether that exposure influenced the federal investigation. These cross-jurisdictional situations are among the most complex Kastigar challenges, and they require thorough investigation of the communications and contacts between state and federal law enforcement during the relevant period.

How is a Kastigar hearing different from arguing that my proffer statements were used against me?

A proffer agreement is a contractual arrangement between you and the government that limits how statements made during a proffer session can be used. Kastigar protection is a constitutional requirement triggered by compelled immunized testimony. The legal standards are different, the burden allocation is different, and the remedy framework is different. Where someone has both proferred and testified under immunity, the two analyses can overlap, but they must be addressed distinctly.

What discovery can I obtain to prepare for a Kastigar hearing?

Defense counsel can seek discovery of the immunized testimony itself, grand jury transcripts to the extent permitted by court order, FBI agent reports and notes documenting the chronology of the investigation, witness lists and contact logs, and communications between agents and prosecutors that may reveal when particular evidence was identified. Courts have discretion over the scope of Kastigar discovery, which means aggressive and well-briefed discovery motions are essential to securing the material needed to mount an effective challenge.

Is a Kastigar challenge worth pursuing if my case also has strong trial defenses?

Yes. A successful Kastigar challenge can eliminate evidence or witnesses that would otherwise be devastating at trial. Even if the challenge does not result in dismissal of the entire indictment, suppressing key witnesses or documents can fundamentally change the government’s trial position, sometimes enough to make a case that appeared strong for the prosecution significantly more difficult for them to win. The two strategies are not in competition; they are complementary.

What if the government says it “walled off” prosecutors who heard immunized testimony from the prosecution team?

This is a commonly cited government safeguard, often called a “taint team” or firewall procedure. Courts scrutinize these arrangements carefully because the effectiveness of a firewall depends entirely on how rigorously it was implemented. If agents or prosecutors on the prosecution side had any exposure to immunized testimony, or received investigative direction from someone who did, the firewall argument weakens considerably. A Kastigar hearing is precisely the mechanism for testing whether the government’s claimed separation was real or merely procedural theater.

How early in a federal investigation should I involve a lawyer if I have given immunized testimony?

The moment you learn that the government is building a case in which your immunized testimony may be relevant, you need counsel. The most critical period is often the interval between when immunized testimony was given and when an indictment is returned. Decisions made during that window, including whether to make additional statements, engage in additional proffers, or seek clarification of the immunity grant’s scope, all have consequences for the eventual Kastigar analysis. Early involvement of counsel gives you the best opportunity to preserve a viable challenge.

Federal Kastigar Representation Across New York City and the Surrounding Region

The Law Offices of Jason Goldman represents clients in federal proceedings throughout New York City and the broader region. This includes cases pending in the Southern District of New York, which covers Manhattan, the Bronx, Westchester County, Rockland County, Putnam County, Orange County, Dutchess County, and Sullivan County, as well as the Eastern District of New York, which covers Brooklyn, Queens, Staten Island, Long Island including Nassau and Suffolk Counties. Clients come to the firm from across the New York metropolitan area, including from the Bronx, Harlem, Washington Heights, the Upper West Side, Midtown, and Lower Manhattan, as well as from Brooklyn neighborhoods including Park Slope, Crown Heights, Bushwick, Williamsburg, and Bay Ridge. The firm also represents individuals from Queens, including Flushing, Jamaica, Astoria, and Forest Hills, and from Staten Island. Beyond the five boroughs, the firm extends its federal criminal defense representation to clients in Westchester, White Plains, Yonkers, Mount Vernon, New Rochelle, and into Rockland and Orange Counties. In New Jersey, where Mr. Goldman is also admitted to practice, the firm accepts federal matters arising from the District of New Jersey, which includes Newark, Trenton, and the broader northern and central New Jersey region. For cases arising outside these core jurisdictions, the firm is available for pro hac vice admission in federal courts throughout the country.

New York City Federal Kastigar Attorney: Protecting the Immunity You Were Promised

When the government granted you immunity and compelled your testimony, it made a constitutional commitment. Enforcing that commitment requires a New York City federal Kastigar attorney who knows how to take the government’s case apart, document by document, and hold prosecutors to their burden in court. Jason Goldman brings prosecutorial experience, federal courtroom fluency, and meticulous preparation to every phase of this challenge, from the initial discovery motions through the hearing itself. Contact The Law Offices of Jason Goldman to discuss your situation and what a Kastigar challenge might mean for your case.