Informant Disclosure at a Suppression Hearing

Why the Suppression Stage Is Different

A motion to suppress asks a narrow question: was the search or seizure lawful, meaning was there probable cause? It does not ask whether the defendant is guilty. That difference drives the disclosure analysis. Because the informant is not a witness to guilt at this stage, the interest in naming him is weaker, and the privilege is correspondingly stronger.

The procedural setting matters too. A motion to suppress must be raised by pretrial motion under Federal Rule of Criminal Procedure 12(b)(3)(C), and if it is not timely raised it is generally forfeited absent good cause. At the hearing itself, the court decides the preliminary questions and, under Federal Rule of Evidence 104(a), is “not bound by evidence rules, except those on privilege.” Hearsay is admissible, and the government routinely proves probable cause through an officer’s account of what a reliable informant reported, without producing the informant.

The result is that the same informant may be treated very differently depending on the stage. At trial, an informant who participated in the offense may have to be disclosed under Roviaro so the defense can prepare. At a suppression hearing, an informant who merely supplied probable cause usually stays anonymous, because the issue is whether the officers had adequate grounds to act, not whether the defendant committed the crime. Understanding that the suppression stage is about the officers’ justification — not the informant’s eyewitness account — is the key to why disclosure motions usually fail here and why the defense attack has to be aimed at the affidavit instead.

McCray: The Privilege Holds at the Probable-Cause Stage

The governing case is McCray v. Illinois. The Supreme Court held that neither the Due Process Clause nor the Confrontation Clause requires disclosure of an informant’s identity at a hearing on probable cause, as long as the officers testify in open court and are subject to cross-examination about the informant’s reliability.

McCray reasoned that the issue at such a hearing “is not guilt or innocence, but… the question of probable cause for an arrest or search.” Where the judge is “convinced, by evidence submitted in open court and subject to cross-examination, that the officers did rely in good faith upon credible information supplied by a reliable informant,” the officers need not name him. The Court rejected the confrontation argument directly, explaining that recognizing the informer’s privilege at a probable-cause hearing does not violate the Sixth Amendment, because the informant is not a witness against the accused on the issue of guilt.

This tracks the settled rule that a warrant may issue on an undisclosed informant’s tip. As McCray noted, federal officers “need not disclose an informer’s identity in applying for an arrest or search warrant,” so long as the magistrate is informed of the underlying circumstances supporting the informant’s reliability. The consequence for the defense is important: a suppression motion that asks the court to order the government to name its probable-cause informant, without more, will almost always fail. The officer takes the stand, testifies to what the informant said and why the informant was believed reliable, submits to cross-examination, and the privilege remains intact. To make headway, the defense must attack something other than the mere fact of anonymity — it must attack the truthfulness of the affidavit itself.

The Franks Exception: Attacking the Affidavit's Veracity

The one route through McCray runs through Franks v. Delaware. Franks lets a defendant challenge the truthfulness of a warrant affidavit, but only after clearing a demanding threshold. It targets the affiant’s honesty, not the informant’s reliability, and it does not, by itself, unmask the informant.

Franks requires a “substantial preliminary showing that a false statement knowingly and intentionally, or with reckless disregard for the truth, was included by the affiant in the warrant affidavit,” and that the false statement was “necessary to the finding of probable cause.” The showing must be specific: the defense must point to the portion claimed to be false, state supporting reasons, and furnish affidavits or explain their absence. “Allegations of negligence or innocent mistake are insufficient.” And if the affidavit still supports probable cause after the challenged material is set aside, no hearing is held at all.

Critically, Franks itself reserved the disclosure question. The Court “need not decide… whether a reviewing court must ever require the revelation of the identity of an informant once a substantial preliminary showing of falsity has been made.” So even a successful Franks proffer does not automatically produce the informant’s name; it produces a hearing on the affiant’s veracity.

How This Plays Out in the Fifth Circuit

The Fifth Circuit applies McCray and Franks together, and its decisions show why informant-disclosure requests at the suppression stage rarely succeed. To attack probable cause built on a tip, the defense must impugn the officer’s honesty, not just question the unnamed source.

In United States v. Arrington, the court held that the informant whose tip led to a search was a “mere tipster” whose disclosure was properly refused, and it explained that under Franks a successful attack on probable cause “would have had to show that the affiant police officers repeated the informant’s tip with knowledge that it was false or with reckless disregard for the truth.” Even proof that the informant’s information was false would not, by itself, defeat the warrant — the falsity has to be the officer’s. That is a high bar, and it explains why simply doubting an anonymous tip is not enough.

Williams v. Brown reinforces the point. The Fifth Circuit observed that Franks “expressly pretermitted whether the revelation of the identity of an informant is required once a substantial preliminary showing of falsity is made,” and it held that any nondisclosure error was harmless where defense counsel already knew the informant’s identity. The takeaway is that the informer’s privilege is routinely protected at the suppression stage, and the defense makes progress only by building a fact-specific, good-faith challenge to the affiant’s truthfulness — not by demanding the name as a matter of course.

Disclosure to Contest Probable Cause vs. Disclosure for Trial

It helps to keep the two disclosure questions separate. Whether the government must name an informant can come out one way at a suppression hearing and the opposite way at trial, because the two proceedings ask different questions and apply different rules. The privilege is stage-specific.

At the suppression stage the question is whether the officers had probable cause, and McCray lets the government prove that through the officer’s testimony without producing the informant. At trial the question is guilt, and if the informant is a participant whose account bears on the offense, Roviaro balancing may require disclosure so the defense can prepare — and if the government calls the informant as a witness, the privilege disappears entirely and ordinary confrontation rights attach. The same person can therefore be a protected probable-cause source at the motion hearing and a disclosable witness at trial.

For the defense, that means matching the argument to the proceeding. A motion to suppress should focus on the lawfulness of the search — cross-examining the affiant on the informant’s reliability and corroboration and, where the facts support it, building a Franks challenge to the affidavit’s veracity. A separate Roviaro motion, aimed at trial, addresses whether the informant’s role in the offense requires disclosure so the defense can investigate and confront. Conflating the two usually loses both: asking a suppression court to disclose a probable-cause informant runs straight into McCray, while waiting until trial to raise a suppression theory runs into the pretrial-motion requirement of Rule 12(b)(3)(C). Precision about which question is being asked, in which proceeding, is what keeps each argument viable.

Practical Steps at a Suppression Hearing

Because a bare demand for the informant’s name will not survive McCray, the defense earns ground at a suppression hearing through the affidavit and the affiant. The work is investigative and specific, aimed at the truthfulness and sufficiency of the officer’s sworn statement rather than at the anonymity of the source.

Several steps follow from the case law. Cross-examine the affiant closely on how the informant’s reliability was established, what corroboration the officers independently developed, and whether the affidavit fairly reported what the informant actually said. Compare the affidavit against reports, recordings, and the officers’ testimony to surface any material misstatement or omission. Where that comparison yields a good-faith basis to allege a knowing or reckless falsehood necessary to probable cause, assemble the specific Franks proffer — identifying the false portion, stating supporting reasons, and attaching affidavits or explaining their absence. And preserve everything by raising the motion pretrial under Rule 12(b)(3)(C), since an untimely suppression motion is generally forfeited.

Where the defense believes the informant’s reliability itself is genuinely in question, it can ask the court to examine the informant or the informant’s file in camera — the sealed procedure covered on the companion page — rather than demanding public disclosure the court is unlikely to order. The realistic objective at a suppression hearing is not to unmask the informant but to test whether the government’s sworn showing of probable cause holds up. Kept on that footing, the motion attacks what the law actually lets the defense attack: the officers’ justification for the search, measured against the affidavit they swore to.

Where This Fits

This guide is one of four situations that arise under the Motion to Reveal Confidential Informant. Start with the parent motion for the overall framework, or move to a related fact pattern:

What the Case Law Says

These decisions—verified against primary sources—control how this issue is litigated. Every case still turns on its own facts.

• McCray v. Illinois, 386 U.S. 300 (1967) — Disclosure of an informant's identity is not required to establish probable cause where officers testify in open court and are cross-examined.
• Franks v. Delaware, 438 U.S. 154 (1978) — A veracity hearing requires a substantial preliminary showing of a knowing or reckless falsehood by the affiant that is necessary to probable cause.
• United States v. Arrington, 618 F.2d 1119 (5th Cir. 1980) — Attacking probable cause requires showing the affiant repeated the tip knowing it was false or with reckless disregard; a mere tipster need not be disclosed.
• Williams v. Brown, 609 F.2d 216 (5th Cir. 1980) — Franks reserved whether an informant's identity must be revealed; nondisclosure was harmless where defense counsel already knew the informant's identity.

General summaries of published opinions for information only — not predictions about any specific case.