Exculpatory evidence and identifications

The Disclosure Trigger: Favorability, Suppression, and the State’s Team

The disclosure question is whether the government withheld favorable evidence that was material to guilt or punishment. Under Brady v. Maryland, a constitutional violation requires three conditions: (1) the evidence was favorable to the accused, (2) the government suppressed it, and (3) it was material. The rule applies whether the prosecutor acted deliberately, negligently, or in good faith.

“Favorable” includes both exculpatory evidence and impeachment evidence. Exculpatory evidence tends to negate guilt, reduce the offense, support a defense, or mitigate punishment. Impeachment evidence tends to show that a prosecution witness is unreliable or biased. Under Giglio, a promise of leniency, immunity, money, a recommendation, or other benefit to a witness is impeachment evidence even if the witness’s substantive testimony otherwise appears to support the prosecution.

Suppression is measured against the defense’s actual access to the information. The prosecution cannot avoid the duty by saying that the trial prosecutor personally did not know what investigators knew. Under Kyles v. Whitley, favorable evidence known to police or others acting on the government’s behalf is generally imputed to the prosecution team. A police file containing a deal with the prosecution’s key witness therefore matters even if the prosecutor never opened that file.

Conversely, evidence is not constitutionally “suppressed” if the defense already possessed it or knew the essential information. Brady is a constitutional disclosure floor, not a general right to inspect every government file or to receive every potentially useful investigative lead. Do not confuse this constitutional doctrine with any broader discovery obligation imposed by a procedural rule or statute.

The third condition, materiality, is the limiting gate. A favorable item is not automatically material, and materiality is not established merely because the item would have been useful. The question is whether the suppressed evidence creates a reasonable probability of a different result, meaning a probability sufficient to undermine confidence in the verdict. This is a lower showing than proving that the verdict probably would have changed, but it requires more than speculation.

This is closed-book-be able to state Brady’s three requirements and Giglio’s impeachment-evidence rule without supplied legal resources.

Materiality and Timing: When Nondisclosure Can Undo a Conviction

Materiality is assessed in the context of the entire record, not by asking whether the suppressed item alone proves innocence. Under Kyles, suppressed favorable evidence must be considered cumulatively. Several modest pieces of impeachment evidence may together undermine confidence in a verdict even though each item viewed separately might not do so.

The role of the witness matters. Impeachment evidence is more likely to be material when the witness is central, corroboration is weak, or the witness’s credibility resolves a disputed issue. A hidden promise to the only eyewitness can be material; the same promise may be immaterial where several independent witnesses and physical evidence establish the same facts.

The Constitution requires disclosure in time for the defense to make effective use of the evidence. Disclosure on the eve of trial is not automatically sufficient merely because it technically occurs before the jury is sworn. The practical question is whether counsel had a meaningful opportunity to investigate, alter strategy, cross-examine, or present the evidence. A late disclosure may be cured by adequate preparation time, but a late disclosure that prevents effective use can produce a constitutional violation.

The consequence follows the same materiality inquiry. If favorable material evidence was suppressed and the defendant was convicted, the conviction cannot stand merely because the prosecutor acted without bad faith; the usual consequence is reversal or a new trial. If the evidence was favorable but immaterial, there is no Brady violation, even though nondisclosure may have violated a separate discovery or professional obligation. Before trial, a court may order disclosure or provide a continuance, but the constitutional issue remains whether the defense received the material evidence in time to use it effectively.

The near-misses are therefore precise:

• Favorable is not the same as material: a useful item still must create a reasonable probability of a different result.

• Police knowledge is not merely personal prosecutorial knowledge: information known to the prosecution team may be imputed to the prosecutor.

• Late is not automatically unconstitutional, and early is not automatically sufficient: ask whether the defense could use the evidence effectively.

• Impeachment is not outside Brady: a concealed witness benefit may be as important as direct exculpatory evidence.

Identification Procedures: Suggestiveness Before Reliability

A due process challenge to an identification begins with state action. The court asks whether law enforcement arranged an identification procedure that was unnecessarily suggestive. If the answer is no, due process does not require a separate reliability hearing merely because the witness may be mistaken; ordinary cross-examination and fact-finding address that risk. This is the principle associated with Perry v. New Hampshire: an accidental or witness-created identification is not subjected to constitutional reliability screening unless the police arranged the suggestive circumstance.

If police arranged an unnecessarily suggestive procedure, the court then asks whether the identification is nevertheless reliable under the totality of the circumstances. Neil v. Biggers identifies five important reliability factors:

1. The witness’s opportunity to view the perpetrator during the crime.

2. The witness’s degree of attention.

3. The accuracy of the witness’s prior description.

4. The witness’s level of certainty at the confrontation.

5. The time between the crime and the identification.

No single factor is decisive. A witness’s confidence does not automatically establish reliability, especially when police wording or procedure may have increased that confidence. The court weighs the quality of the original observation against the suggestiveness of the procedure.

A lineup is not unconstitutional simply because the suspect is present among fillers or because the witness chooses the suspect. The issue is whether the suspect was made to stand out or officers communicated the desired answer. A properly constructed lineup does not require people who are identical in every physical respect.

A showup is more suggestive because the witness is shown only one person. It is not per se unconstitutional. Prompt presentation near the scene may serve a legitimate investigative need: the witness can confirm that officers detained the right person, or officers can release an innocent person quickly. Delay, repeated exposure, unnecessary transportation, or explicit police pressure can make the showup unnecessarily suggestive.

A photo array is judged in the same way. The Constitution does not require a particular number of photographs or mandate simultaneous rather than sequential presentation. But a suspect’s photograph should not be visually or verbally singled out. An officer’s statement that the suspect is “in the group,” a distinctive border, unusual lighting, a different photograph size, or feedback after an initial choice may contribute to suggestiveness.

A voice identification receives the same due process analysis when police arrange the witness’s comparison of voices. The important distinction is between the physical voice sample and the procedure used to identify its speaker. A compelled exemplar or recording is not automatically suggestive. The danger arises when the suspect’s voice is presented alone, repeated while fillers are not, or accompanied by instructions that signal the expected selection.

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If the pretrial identification is excluded, a later in-court identification is not automatically permitted merely because the witness is now confident. The prosecution must show an independent source for the in-court identification, such as the witness’s untainted opportunity to observe the perpetrator during the crime. A confidence created by the unconstitutional procedure is not an independent source.

After an armed robbery, the victim told police that the robber was a man of medium height wearing a red cap. The victim observed the robber’s face for thirty seconds under bright lighting and gave an accurate description.

Two days later, a detective showed the victim six photographs. Five fillers matched the description, but the defendant’s photograph was the only one with a red border and was noticeably larger. Before displaying the array, the detective said, “The robber is in this group.” The victim selected the defendant and expressed 80 percent confidence.

The defendant moves to suppress the identification.

Three Constitutional Close Calls: Disclosure and Identification

High-Yield Points - ⚡ Biggest Takeaways

Brady requires favorable evidence, government suppression, and materiality; impeachment evidence counts. Police knowledge is generally imputed to the prosecution team, but materiality is assessed cumulatively. For identification, ask state action, unnecessary suggestiveness, and then totality-based reliability.