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The Exclusionary Rule

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Admissible Evidence:
Evidence permitted to be introduced at trial. Only relevant evidence is admissible, which means the evidence must tend to make more or less probable the existence of some fact material to the case, or some fact otherwise of consequence to making a determination in the case. Evidence that tends to establish facts from which one could then infer that some material fact is more or less probable is also admissible as relevant evidence.

Excluded Evidence: 
Evidence that may be otherwise relevant and admissible but is not admitted and may not be considered in the decision-making process for some reason other than irrelevance.

Fruits of the Poisonous Tree Doctrine: 
Any evidence gathered as a result of an illegal search, even at a time later than the illegal search itself, will be excluded from evidence.

Good Faith: 
A reasonable, honest belief lacking malice or ill intent and without intention to defraud. The concept of good faith appears in many areas of law, although it is intangible and determined based on the totality of the circumstances rather than some hard and fast rule.

The Fourth Amendment to the Constitution of the United States reads:

"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrant shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the person or things to be seized."

The Exclusionary Rule is available to a Defendant in a criminal case as a remedy for illegal searches that violate the rights set forth in the Fourth Amendment. When applicable, the rule dictates that the evidence illegally obtained must be excluded as evidence under the Fourth Amendment. See Mapp v. Ohio, 367 U.S. 643 (1961). One important corollary to the Exclusionary Rule is the “fruit of the poisonous tree” doctrine. This rule holds that in addition to the material uncovered during the illegal search being inadmissible, any evidence that is later gathered as an indirect result of the illegal search will also be excluded. See Wong Sun v. United States, 371 U.S. 471.

EXAMPLE (1): The police illegally search D’s car and find drugs. The drugs will be excluded as evidence in the case against D in accordance with the Exclusionary Rule.

EXAMPLE (2): The police conduct an illegal search of D’s home and find a map showing the location of a well-hidden, remotely located outdoor marijuana field. The police go to the field and seize the marijuana. Under the doctrine of "fruit of the poisonous tree," the marijuana will be excluded as evidence in the case against D as it stemmed directly from an illegal search.

There are two important exceptions to the “fruit of the poisonous tree” doctrine:

  1. If the police had an independent source of knowledge of the evidence aside from the fruits of the illegal search, then the doctrine will not exclude the discovered evidence.
  2. If discovery of the evidence was "inevitable", the evidence may be admitted, as it was not then the illegal search that caused the evidence to be found. “Inevitable” is a strong word, and in order to admit evidence under this exception, a court must find that police would have discovered the evidence whether or not they conducted the unreasonable search.

EXAMPLE (1): The police conduct an illegal search of D’s home and find a map showing the location of an outdoor marijuana field located 50 feet behind the loading dock of a busy commercial strip. The police go to the field and seize the marijuana. The marijuana may be admitted as evidence by a court. Although the police were led to the field by information discovered during an illegal search, a court could find that discovery was inevitable, given the field's proximity to heavily used areas and the fact that the field was not well hidden.

EXAMPLE (2): Officer Brady illegally searches Donald’s barn and discovers documents identifying Donald as the culprit behind an internet scam. The next day a confidential informant e-mails Officer Brady the same documents. The documents are admissible as evidence because there was an independent source for the evidence besides the illegal search.

EXAMPLE (3): The police perform an illegal search of Fred’s residence and discover stolen goods. On the counter they find a notepad on which Fred wrote the following: Reminder - place newspaper ad “Computer stuff for sale; cheap and hot! Call Fred 555-1234.” Based on this, the police call the number and that leads them to more evidence against Fred. The discovery was not inevitable as the ad never ran. The evidence will be excluded.

There is also one important exception to the Exclusionary Rule. When a search is conducted with a good faith belief that it is a legal search, the evidence discovered may be admitted. See United States v. Leon, 468 U.S. 897 (1984). If the officer believes that a warrant is not required for a search, or conducts a search pursuant to a warrant, which he believes to be valid, the officer can be said to be acting in good faith. On the other hand, if he knows or should have known of some defect in the warrant (see following materials on valid warrants) the good faith exception will not apply. Recently, in Herring v. United States 555 U.S. 135 (2009), the Supreme Court made clear that in order “[t]o trigger the exclusionary rule, police conduct must be sufficiently deliberate that exclusion can meaningfully deter it, and sufficiently culpable that such deterrence is worth the price paid by the justice system.”  In other words, when police are not deliberately violating the fourth amendment and are acting under the auspices that their conduct is permissible, suppression is not merited.  

EXAMPLE (1): Officer Careful executes a search in accordance with a search warrant obtained from Judge Hatchet. Unknown to Officer Careful, Judge Hatchet issued the warrant after an incorrect finding of probable cause. Although the search was illegal, the evidence is not tainted and does not fall under the Exclusionary Rule because Officer Careful acted in good faith upon the Judge’s finding. If otherwise relevant and admissible, the evidence may be considered.

EXAMPLE (2): Judge E. Doe issues a warrant based on Officer Ellay’s sworn testimony that he saw Al Bronco removing stolen shoes from his trunk and carrying them into his home in Big Town, California. The warrant is made out for “that property owned by Mr. Al Bronco in Big Town, California.” Unbeknownst to Judge E. Doe, Al owns several houses in Big Town, one in which his mother lives and the others which he rents out. Officer Ellay is aware of this, and executes the search of the intended home. Because the warrant is not "precise on its face” (see section on Warrant Requirement below), Officer Ellay’s search cannot be said to be in good faith and this exception to the Exclusionary Rule will not apply. Any evidence discovered from the search or stemming there from will be excluded.

It is important to note that the exclusionary rule is inapplicable in the following circumstances: grand juries hearings; civil proceedings; alleged statutory violations (not implicating the Constitution); and when used for purposes of impeachment. 


To determine if a search is unreasonable, refer to Evidentiary Search Overview chart at end of Subject 6.