Also known as:tainting evidence · taints evidence · evidence taint · illegally obtained evidence
Written by attorneys · grounded in primary & secondary sources — see below
Evidence obtained directly or indirectly through a constitutional violation. Such evidence is presumptively inadmissible under the exclusionary rule unless the connection to the illegality has been sufficiently attenuated or an exception such as independent source or inevitable discovery applies.
Sources & Authorities
How it applies
Common Examples
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Isolated Database Error Limits Suppression
Theresa Tucker was arrested at an airport hangar after officers relied on a live alert from a flawed aviation database that had not been updated despite repeated internal warnings. A search incident to arrest uncovered design plans and contraband in her locker. Because the database lapse reflected at most isolated negligence rather than deliberate misconduct, the court admitted the items after balancing the limited deterrent value of exclusion against its social costs.
Good Faith Reliance on Warrant
Tori Taylor's home was searched pursuant to a warrant later found to lack probable cause because an affidavit contained stale information. Officers had relied in objective good faith on the warrant issued by a neutral magistrate. The court admitted the seized documents because the officers' conduct did not warrant the deterrent sanction of suppression.
Select any source to read its text and confirm it supports the definition.
Cases
Dictionaries
United States v. Leon468 U.S. 897 (1984)
Inevitable Discovery of Remains
Tanya Tang led officers to a child's body after improper questioning. Search teams were already closing in on the same location through an independent, ongoing grid search that would have located the remains within hours. The court admitted evidence of the body's location and condition because it would have been discovered lawfully regardless of the violation.
Nix v. Williams (Williams II)467 U.S. 431 (1984)
Immunized Testimony Bars Derivative Use
Tara Tran testified under a grant of use immunity. Prosecutors later introduced documents obtained by following leads from that testimony. The court suppressed the documents because they were derived from the compelled statements and the government failed to prove an independent source.
Kastigar v. United States406 U.S. 441 (1972)
Harmless Admission of Tainted Statement
Tyrone Tran gave an unwarned statement that was later introduced at trial. Overwhelming independent eyewitness testimony and physical evidence established his guilt beyond a reasonable doubt. The court upheld the conviction because the error did not contribute to the verdict.
Chapman v. California386 U.S. 18, 24, 87 S.Ct. 824, 17 L.Ed.2d 705 (1967)
State Court Applies Exclusionary Rule
Thaddeus Tran was prosecuted in state court after state officers conducted a warrantless search of his briefcase at an airport following routine screening. The search yielded export documents. The court suppressed the documents because the Fourth Amendment violation required exclusion in state proceedings.
Mapp v. Ohio367 U.S. 643 (1961)
Common questions
Frequently Asked
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When does the taint of an unlawful search dissipate so that later evidence becomes admissible?+
The connection between the illegality and the evidence must become sufficiently attenuated through factors such as time, intervening circumstances, or the flagrancy of the misconduct. Voluntary acts by third parties or formal legal processes like grand jury subpoenas can break the causal chain.
Supporting sources
Does the exclusionary rule automatically bar all evidence discovered after a constitutional violation?+
No. Suppression turns on whether the evidence is a direct or indirect product of the illegality and whether any exception such as independent source, inevitable discovery, or attenuation applies. Courts also weigh the culpability of the officers and the deterrent value of exclusion.
Supporting sources
Can evidence obtained through an unlawful search be used to impeach defense witnesses other than the defendant?+
No. Illegally obtained evidence may be used only to impeach the defendant's own testimony. Extending its use to other defense witnesses would undermine the deterrent purpose of the exclusionary rule.
Supporting sources
388 U.S. 218 (1967)Evidence
…Footnotes [^maj-1]: Holt was decided before Weeks v. United States , 232 U. S. 383 , fashioned the rule excluding illegally obtained evidence in a federal prosecution. The Court therefore followed Adams v. New York , 192 U. S. 585 , in holding that, in any event, "when he is exhibited, whether voluntarily or by order, and even…