Evidence Procedure

For officers and detectives, California v. Greenwood supports the use of curbside trash pulls as an investigative technique under the federal Fourth Amendment. If garbage has been placed out for collection in an area accessible to the public and outside the home’s curtilage, officers generally do not need a warrant to seize and search it.

For police officers and detectives, Segura v. United States is an important reminder that a valid warrant can preserve evidence only when the warrant is truly independent of any earlier mistake. If officers enter too soon without a warrant, they risk suppression of anything discovered during that entry.

United States v. Janis: for officers, the first lesson is that Fourth Amendment rules still control searches and seizures. United States et al.

Illinois v. Gates is a core warrant case for officers because it confirms that probable cause is based on the whole picture. A strong affidavit should explain why, taken together, the facts create a fair probability that evidence will be found at the location.

United States v. Johnson matters to police because it shows that a constitutional rule can affect cases already in the pipeline, not just future arrests. If officers made a warrantless and nonconsensual home entry for a routine felony arrest before Payton, and the case was still on direct review when Payton was decided, the government could not simply say the arrest was valid because it occurred before Payton.

For officers and detectives, Duckworth v. Eagan is a reminder that Miranda warnings do not have to be word-for-word identical to the language in Miranda v. Arizona. What matters is whether the suspect is clearly told the substance of the rights: the right to remain silent, the possible use of statements in court, the right to counsel before and during questioning, and the right to appointed counsel if the suspect cannot afford one.

For officers, detectives, and supervisors, New York v. Harris should not be read as permission to enter a home without a warrant whenever probable cause exists. Payton remains the controlling rule: absent valid consent or exigent circumstances, police generally need an arrest warrant before crossing the threshold of a suspect’s home to make an arrest.

Withrow v. Williams does not change what officers must do during custodial interrogation. The basic Miranda rules remain the same: before custodial interrogation, give the required warnings; obtain a valid waiver before questioning; stop or adjust questioning when the suspect invokes the right to remain silent or the right to counsel; and avoid coercive tactics that could create separate voluntariness problems.

For officers, detectives, and supervisors, Perry v. New Hampshire draws an important but limited constitutional line. If a witness makes an identification under circumstances the police did not arrange, federal due process does not automatically require suppression just because the situation was suggestive.

For officers, the key takeaway is narrow but important: Immigration & Naturalization Service v. Lopez-Mendoza is about civil deportation proceedings, not ordinary criminal prosecutions. It should not be read as permission to ignore the Fourth Amendment.

Nix v. Williams is important for officers because it explains why courts sometimes admit evidence even when a defendant claims there was a constitutional problem with the search. If the evidence would have been found through a lawful arrest, search incident to arrest, inventory, booking process, or other legitimate procedure, suppression may not be required.

For officers, detectives, and supervisors, James v. Illinois reinforces a simple point: evidence obtained in violation of the Constitution may be lost for more than just the prosecution’s main case. It also may be unavailable to impeach defense witnesses.

McDonald v. City of Chicago: mcDonald matters to police because it means local firearm enforcement must account for the Second Amendment. A city ordinance is not insulated from constitutional review simply because it is local.

Sanchez-Llamas v. Oregon: for police officers, the safest and most professional practice is to ask about foreign nationality when appropriate after arrest or detention and to give consular-notification advisements when the person is a foreign national. If the person asks for the consulate to be notified, the agency should follow its procedures for making that notification.

United States v. Leon, 468 U.S. 897 (1984), held that the exclusionary rule generally does not bar evidence seized by officers who reasonably rely in good faith on a search warrant later found invalid. The decision created a major Fourth Amendment doctrine while preserving suppression for serious police misconduct or plainly unreliable warrants.

In Herring v. United States, 555 U.S. 135 (2009), the Supreme Court held that evidence found after an arrest based on an outdated warrant record did not have to be suppressed. The exclusionary rule turns on whether suppression would deter sufficiently culpable police conduct, not on every negligent recordkeeping mistake.

Brady v. Maryland requires prosecutors to disclose material evidence favorable to the accused when it bears on guilt or punishment. The rule protects the fairness of criminal trials and applies regardless of whether the prosecution acted in good or bad faith.