The Fruit of the Poisonous Tree Doctrine

The fruit of the poisonous tree doctrine is an evidentiary rule that, together with the exclusionary rule, gives the Fourth Amendment of the Constitution its teeth. Prior to 1914, warrantless and other shady searches conducted by law enforcement were quite common in America and were detrimental to those facing criminal charges from the evidence obtained during the searches.

However, in 1914, things changed. The United States Supreme Court took up the case of Weeks v. United States, 232 U.S. 383, 34 S. Ct.341, 58 L. Ed. 652 (1914), wherein a warrantless search of a home belonging to a man named Fremont Weeks was searched and the evidence that was found was used to convict him of illegal gambling. The case wended its way to the land’s highest court, where ultimately the justices ruled that evidence obtained in this manner was not able to be used in court. The man had his conviction overturned and the exclusionary rule was introduced.

The exclusionary rule was the precursor to the fruit of the poisonous tree doctrine. This legal metaphor regards tainted evidence (fruit) obtained through illegal searches or other police misconduct (the poisonous tree) as inadmissible in court. For example, you are driving and are stopped by police because you were speeding. You are clearly not impaired by drugs or alcohol, yet the police ask to search your vehicle. You politely refuse to grant consent, yet the search is done anyway and the police find a pound of marijuana in the trunk of your car. A good criminal defense attorney should be able to have your charges dismissed because the search itself was illegal.

This rule would also apply if, during questioning by police, a suspect asks for access to a lawyer but police ignore the request and keep questioning him or her. Hours later, under duress and tired from the interrogation, the suspect winds up confessing to robbing a bank. Such a confession is now tainted because the police failed to stop questioning the suspect after a request for an attorney was made. As with most rules, however, there are exceptions to this exclusion.

The Four Main Exemptions

  1. The evidence was found, at least in part, as a result of another untainted or independent source.
  2. Despite the tainted source, the evidence would inevitably have been discovered anyway.
  3. Attenuation exists between an illegal activity and its discovery by law enforcement.
  4. While the search warrant (or lack thereof) was not intrinsically valid, it was executed by agents of the government who were found to be acting in good faith.

As you can see, the rules regarding the admissibility of evidence in criminal cases are complex and subject to nuance and interpretation. Prosecutors will argue vociferously in court that the evidence should be introduced at trial, is not tainted and was legally obtained. A defendant without a criminal defense attorney in possession of a vast knowledge of evidentiary rules and exceptions is at a distinct disadvantage at trial. But hope is not lost if you are convicted on bad evidence, as this can be taken up on appeal with the conviction ultimately being overthrown by a higher court’s ruling.

The information on this page is meant to provide a general overview of the law. The laws in your state and/or city may deviate significantly from those described here. If you have specific questions related to your situation you should speak with a local attorney.

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