Illegal Searches and Your Criminal Case

Sometimes, the prosecution and courts can still use illegally seized evidence.

When law enforcement members disregard the Fourth Amendment and conduct an unreasonable search, often the evidence they procure will be ruled inadmissible in court. But not always.  (To learn about one important exception, see  Police Searches and the Good Faith Exception.)


Though many critical rights come from the U.S. Constitution, states have their own constitutions and statutes. State law often provides protections that are similar, if not identical, to the those the federal Constitution gives. But occasionally state law offers expanded rights. Keep this potential expansion in mind when reading about general criminal law principles. It could be, for example, that evidence that would be admissible under the federal Constitution is inadmissible under state law.

For more on applicable law and your rights, see this  note from our editors.

Using Illegally Seized Evidence

Here are some situations where items or evidence seized illegally may still be used:

  • Sentencing. A judge may consider improperly seized evidence at sentencing.
  • Civil cases and deportation hearings. Likewise, evidence improperly seized may be introduced.
  • Impeachment. In some instances, a prosecutor may use illegally seized evidence to “impeach” a witness (to attack the witness’ credibility).

Example: Flo is on trial for possessing illegal drugs. During a pretrial hearing, the trial judge ruled that the police had illegally seized a gun from Flo’s bedroom, and that the prosecutor could not admit the gun into evidence. While testifying, Flo states, “I’ve never owned a weapon of any kind.” This testimony allows the prosecutor to use the illegally seized gun to attack the credibility of Flo’s testimony. Even though the search wasn’t legal, the prosecutor may show Flo the illegally seized gun and ask her a questions such as, “This gun belonged to you, correct?” “Your testimony that you’ve never owned a weapon was incorrect, wasn’t it?”

Using Illegally Seized Evidence to Find Other Evidence

Officers generally cannot use illegally obtained evidence as a means to find more evidence, because of a legal rule colorfully known as the “fruit of the poisonous tree" doctrine. This rule makes inadmissible any evidence that police officers seize or any information that police officers obtain as a direct result of an improper search or seizure. (The tree is the evidence that the police illegally seize in the first place; the fruit is the evidence that results from the illegally seized evidence. Both tree and fruit are inadmissible at trial.) The fruit of the poisonous tree doctrine removes what would otherwise be a big incentive for police officers to conduct illegal searches.

(For a related issue, see  If the Police Find Evidence Because of a Miranda Violation, Is the Evidence Inadmissible?)

Example: Officer Wiley arrests Eddie for selling phony telephone cards. A judge ruled that Officer Wiley had illegally entered Eddie’s home and improperly seized a map showing the location where Eddie hid the phone cards. Officer Wiley then used the map to find and seize the phone cards. At trial, neither the map (the poisonous tree) nor the phone cards (the fruit) are admissible in evidence.

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